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The genus Cycas (Cycadaceae) in Vietnam.

   I. Abstract
  II. Introduction
 III. Generic Concepts
  IV. Species Concepts
   V. Hybridism
  VI. Conservation
 VII. Taxonomic Treatment
VIII. Species Known from China That May Be Expected to Occur in Vietnam
  IX. Doubtful and Excluded Names
   X. Acknowledgments
  XI. Literature Cited


II. Introduction

The genus Cycas was first recorded from Vietnam by de Loureiro (1793), with his description of the new species Cycas inermis, based on collections he had made in Cochin China (southern Vietnam) in 1787. Although the third species of Cycas to be described, C inermis has at no stage been properly understood. Since that date, eight additional taxa have been described as new in the catalog of the flora of Vietnam. The first of these were C tonkinensis and C bellefontii, described by Linden and Rodigas (1885, 1886). Both were described from living plants in cultivation that had been collected in Tonkin (northem Vietnam), and no herbarium material was preserved (see doubtful and excluded names below). Warburg described C. balansae from near Hanoi in 1900, and Thiselton-Dyer described C. rnicholitzii from Annam (central Vietnam--Laos) in 1905. Finally, Leandri described C. chevalieri from northern Vietnam and C. pectinata vat. elongata from southern Vietnam in 1931. Taxa previously known from other areas that have also been recorded from Vietnam are C. pectinata Buch.-Ham. and C. siamensis Miq. The names C. circinalis L. and C. rumphii Miq. have at different times been wrongly applied to Vietnamese taxa. Other names misapplied to plants from Vietnam have been C. undulata and C. rniquelii (see excluded names, below).

The comprehensive account of the genus by de Candolle (1868), recorded only Cycas inermis from the region of Vietnam, largely on the basis of the notes published by de Loureiro. De Candolle had also followed Miquel (1851) in misapplying the name C. inermis to specimens of C. revoluta (see below). Pilger (1926) recorded only C siamensis and C. micholitzii from Vietnam. Schuster (1932) included C. tonkinensis in C. circinalis var. undulata, but also included material of the C rumphii complex from the Marianas, together with material from Vietnam, in a confused concept. Schuster also recognized C. siamensis and C. micholitzii from Vietnam, but then held C. inermis and the quite unrelated C balansae as subspecies of C. siamensis. Leandri (1931) had added C. immersa to the Vietnam catalog, and subsequently Schuster correctly placed C. immersa in the synonymy of C. siamensis (in subsp, siamensis sensu Schuster), although he included a number of unrelated species in the other subspecies he erected within C. siamensis.

The regional account by Leandri (1931) listed 10 species occurring in Vietnam but misapplied the names Cycas circinalis, C. rumphii, and C immersa. Ho and Duong (1960) recorded only 7 species but again misapplied the three names above. Ho later (1991) added an eighth species, C. inermis, again misapplying the above names and the latter name as well. Hiep and Vidal (1996) recorded 8 species, correctly placing C immersa in the synonymy of C. siamensis but otherwise followed the same misapplications (discussed below under relevant species). More recent studies have gradually shown that the cycad flora of Vietnam is substantially richer--in fact, probably the richest of the region (Hiep & Loc, 1997, 1999).

III. Generic Concepts

The recently described genus Epicycas (de Laubenfels & Adema, 1998) is herein placed in the synonymy of Cycas. When characters that are inconsistent are excluded, the new genus is defined solely on the possession of a bulbous underground base. However, even this character is neither wholly consistent within species nor restricted to the species placed in the new genus. Moreover, of the species placed within the new genus, a number have what are clearly sister species that were left in the genus Cycas; for example. Cycas siamensis and C. elongata (both placed in Epicycas) are closely allied to C. pectinata, and C. taiwaniana is close to the group placed in Epicycas tonkinensis (see excluded species below). Grouping characters (or synapomorphies) supporting these relationships are discussed below under the relevant sections.

IV. Species Concepts

The genus Cycas shows a complex geographical replacement pattern throughout its range, often with many closely related entities. Although these taxa are often similar in many respects, the homoplasy evident in the defining characters does not always allow unequivocal aggregation into groups that could be treated as species with subordinate subspecies. In order to satisfactorily separate and recognize groups of populations that show real, albeit sometimes small, differences, these groups are treated herein as distinct species. This rather narrow view of species is considered preferable to the arbitrary submerging of these recognizably distinct and true-breeding groups of populations into broader and less meaningful "species" and the consequent loss of information on the real diversity of these plants.

Species definition is complicated by the variability of some of the characters that have been traditionally used to separate taxa. Development of spines on petioles is often variable within populations and often changes with age in most taxa. Microsporophylls vary considerably in size and shape from base to apex of the cone; in particular, the apical spine is reduced or absent on the lowermost sporophylls, gradually increasing in size toward the apex or toward the center of the cone (see also Amoroso, 1986). Megasporophylls also vary, often widely, in size, shape of lamina, and number of ovules. This can depend on their position within a growth flush, the first and last produced often being markedly smaller and less elaborate than those in the center.

Because many herbarium collections are fragmentary, incomplete, and often sterile, many characters are often not present or recorded. Comprehensive field study is thus essential to the understanding of the ranges of variation and of characters that distinguish taxa. All species discussed herein have been examined in the field.

V. Hybridism

The problem of hybridism in Cycas was introduced elsewhere (Hill, 1992, 1996). The lack of pollinator specificity, when combined with the apparently weak inherent fertility barriers, results in the major reproductive barrier between Cycas species in nature being geographical separation. Natural populations of Cycas species are usually widely separated geographically, and some breakdown of reproductive isolation would therefore be expected where different species have spread to within pollination range of each other.

A number of natural occurrences are postulated to be of just such hybrid origin. These are morphologically intermediate between the putative parent species and, in the cases of postulated hybrid swarms, show the high degree of variability to be expected from Mendelian segregation in the second and later generations. Hybrids and hybrid or intergrading populations have been recorded from throughout the range of Cycas, wherever different species grow in relatively close proximity. Examples from Vietnam include intergradation between C. dolichophylla and C. ferruginea east of Thai Nguyen, between C. collina and C. dolichophylla west of Moc Chan, and between C. dolichophylla and C. bifida west of Thai Nguyen (all are cited below under the first species of the pair listed).

VI. Conservation

Populations of many Asian species appear to have declined, sometimes dramatically, over the past century. However, there is no comparative data to support this impression, and evidence for the decline is largely anecdotal and circumstantial. Several causative factors for this decline can be observed in action today, however, even though quantitative data on the effects are not available. Two principal threats to cycads exist in Vietnam at present, habitat loss and selective removal of plants from the wild for trade or utilization. Some but not all species occur in reserved areas already proclaimed, but enforcement within these areas is sometimes difficult. There is, however, a growing interest in habitat and species conservation within Vietnam, and additional reserved areas are being evaluated and declared.

Only one Vietnamese species, Cycas micholitzii, was listed in the now out-of-date (for this region) IUCN 1997 Red List of Threatened Plants (Waiters & Gillet, 1998). Species treated below are allocated provisional conservation status codes under the new coding system devised by the IUCN (IUCN, 1994). Conservation status of all species is summarized in Table I.

VII. Taxonomic Treatment

CYCAS L., Sp. Pl.: 1188. 1753.

LECTOTYPE: Cycas circinalis L.; designated by Stevenson in Jarvis et al. (1993).

Dioecious palm-like shrubs with aerial or subterranean, pachycaulous, cylindrical stems clad with persistent leaf-bases. Leaves loosely pubescent when young, pinnate, spirally arranged, produced in seasonal growth flushes interspersed with cataphylls, lower pinnae often reduced to spines. Longitudinal ptyxis erect or rarely reflexed, horizontal ptyxis circinate. Pinnae with a single thick midrib and no lateral veins; stomata confined to abaxial surface in most species; individual ptyxis involute. Trichomes transparent, branched or simple. Microsporophylls aggregated into determinate cones and bearing numerous microsporangia (pollen sacs) on abaxial surfaces, with a simple sterile apex, which is often produced into an upturned spine; microsporangia opening by slits; pollen cymbiform, monosulcate. Megasporophylls spirally arranged in an indeterminate terminal rosette with the central axis continuing vegetative growth. Ovules two to many (rarely one), marginally inserted on the stipe and directed obliquely outward ("ascending"); sporophyll apically dilated into a pinnatifid, pectinate, toothed, or entire lamina. Seeds with a yellow, orange, or brown fleshy outer sarcotesta and with or without spongy tissue beneath the inner woody sclerotesta. Endosperm haploid, derived from the female gametophyte. Embryo straight, with 2 cotyledons that are usually united at the tips and a very long, spirally twisted suspensor; seeds platyspermic; germination cryptocotylar.

About 90 species, chiefly Australian (27 species) and Indo-Chinese (about 35 species). The genus also occurs in the Malesian region, Japan, and India, extending to Micronesia and Polynesia, Madagascar, and East Africa. Plants are commonly understory shrubs in forest, woodland, or savanna habitats. Four sections have been recognized (Hill, 1995), although there has been disagreement on subgeneric division (Wang, 1996; de Laubenfels & Adema, 1998), and, in the light of improved understanding of the genus, none of the proposed systems would appear entirely adequate (Hill, 2004). Three clear groups, regarded below sections, occur naturally in Vietnam (Fig. 1), and a fourth is represented by one widely cultivated species. Vietnam has the greatest diversity at the sectional level and the highest number of species of any country except Australia.

[FIGURE 1 OMITTED]
Key to sections occurring in Vietnam

1. Ovules tomentose                             Section Asiorientales *
1. Ovules glabrous
  2. Microsporangiate sporophylls soft,
     lacking an apical spine or with
     a very slender, tightly appressed
     apiculus                                     Section Stangerioides
  2. Microsporangiate sporophylls hard,
     with a distinct apical spine
    3. Megasporophyll pectinate                    Section Indosinenses
    3. Megasporophyll entire or dentate,
       not deeply
       pectinate                                          Section Cycas

                    Key to the species in Vietnam

1. Pinnae simple
  2. Megasporophyll pectinate
    3. Pinnae with margins revolute or
       strongly recurved                                  C. revoluta *
    3. Pinnae with margins fiat or
      moderately recurved, never revolute
      4. Microsporangiate cones soft;
         sarcotesta not fibrous; sclerotesta
         with more or less rugose
         ornamentation
        5. Apical spine of megasporophyll
           lamina dilated, markedly
           different from lateral spines
          6. Leaves flat
            7. Megasporophyll lamina
               35-55 x 30-50 mm                    15. C. sexseminifera
            7. Megasporophyll lamina
               65-120 x 60-80 mm                      14. C. ferruginea
          6. Leaves keeled                           16. C. tropophylla
        5. Apical spine of megasporophyll
           lamina not dilated, similar to
           lateral spines
            8. Microsporophyll with a
               distinct terminal spine
              9. Leaves more than 1 m long,
                 pinnae 14-20 mm wide
                10. Leaves to 360 cm long,
                    with 100-160 pinnae;
                    megasporophyll lamina
                    with 6-9 teeth, seeds
                    5-40 mm long                        6. C. tanqingii
                 10. Leaves to 240 cm long,
                     with 80-110 pinnae;
                     megasporophyll lamina
                     with 15-25 teeth, seeds
                     18-27 mm long                     7. C. chevalieri
              9. Leaves less than 1 m long,
                 pinnae 10-15 mm wide                8. C. hoabinhensis
                 8. Microsporophyll lacking
                    a terminal spine
                   11. Petiolar spines 4-10
                       mm long
                     12. Pinnae 10-13 mm
                         wide, narrowed
                         and tapered
                         at base                         4. C. balansae
                     12. Pinnae 13-21 mm
                         wide
                       13. Pinnae abruptly
                           rounded at base;
                           petiole
                           short                   10. C. dolichophylla
                        13. Pinnae tapered
                            at base;
                            petiole long                 5. C. aculeata
                   11. Petiolar spines 1-3
                       mm long
                          14. 5-10 leaves in
                              crown, leaves with
                              100-200 pinnae,
                              pinnae 10-14
                              mm wide                9. C. brachycantha
                          14. 1-5 leaves in
                              crown, pinnae more
                              than 15 mm wide
                          15. Leaves with more
                              than 100 pinnae;
                              microsporangiate
                              cones 25 cm long, 7
                              cm diam. or more            1. C. collina
                          15. Leaves with less
                              than 110 pinnae;
                              microsporangiate
                              cones 20 cm long, 6
                              cm diam. or less
                            16. Teeth on
                                megasporophyll
                                lamina 40-100 mm
                                long                        2. C. fugax
                            16. Teeth on
                                megasporophyll
                                lamina 15-25 mm
                                long                3. C. simplicipinna
  4. Microsporangiate cones firm; sarcotesta with a fibrous layer;
       sclerotesta not ornamented
                            17. Pinnae densely
                                tomentose when
                                young,retaining
                                tomentum until
                                fully expanded;
                                pinnae reducing
                                gradually to
                                spines toward
                                leaf base              23. C. siamensis
                            17. Pinnae losing
                                tomentum before
                                reaching full
                                expansion;
                                pinnae not
                                gradually reducing
                                toward base
                            18. Microsporangiate
                                cones up to 20 cm
                                long, 5 cm diam.;
                                plants acaulescent;
                                leaves distinctly
                                keeled (opposing
                                pinnae inserted at
                                90-130[degrees] on
                                rachis)              22. C. lindstromii
                            18. Microsporangiate
                                cones 25-60 cm
                                long,5-30 cm
                                diam.; at
                                least some plants
                                developing an
                                aerial stem;
                                leaves flat or
                                openly keeled
                                (opposing pinnae
                                inserted at more
                                than 150[degrees]
                                on rachis)
                              19. Microsporophylls
                                  with an attenuate
                                  spinose tip 17-40
                                  mm long;
                                  microsporangiate
                                  cones more than
                                  16.5 cm diam         17. C. pectinata
                              19. Tips of
                                  microsporophylls
                                  not exceeding
                                  16 mm;
                                  microsporangiate
                                  cones less than
                                  15 cm diam.
                              20. Petiole short
                                  (10-20 cm long,
                                  10-20% of total
                                  leaf length;
                                  petiole
                                  spinescent for
                                  80-100% of
                                  length
                                21. Pinnae 6-8
                                    mm wide,
                                    seedling
                                    pinnae
                                    5-7 mm
                                    wide 19.                C. elongata
                                21. Pinnae 7-10
                                    mm wide, seedling
                                    pinnae 7-10 mm
                                    wide               20. C. pachypoda
                              20. Petiole long
                                  (20 cm long or
                                  longer,
                                  15-50% of
                                  total leaf
                                  length); petiole
                                  unarmed or
                                  spinescent for
                                  less than 70%
                                  of length
                                 22. Apical spine
                                     of microsporophyll
                                     less than 6 mm
                                     long              18. C. clivicola
                                 22. Apical spine
                                     of microsporophyll
                                     more than 8 mm
                                     long            21. C. condaoensis
  2. Megasporophyll not pectinate
                                 23. Lateral spines on
                                     megasporophylls
                                     distinct; leaves
                                     60-90 cm long;
                                     seeds with
                                     fibrous sarcotesta;
                                     spongy layer
                                     absent              24. C. inermis
                                  23. Lateral spines
                                      on megasporophylls
                                      indistinct; leaves
                                      150-250 cm long;
                                      seeds lacking a
                                      fibrous sarcotesta;
                                      spongy layer
                                      present          25. C. litoralis
1. Pinnae dichotomously divided
                                   24. Pinnae themselves
                                       pinnately
                                       divided      13. C. multipinnata
                                   24. Pinnae
                                       dichotomously
                                       divided
                                       only
                                    25. Microsporangiate
                                        cones more
                                        than 6 cm diam.,
                                        20 cm long;
                                        median micro
                                        sporophylls
                                        rounded           12. C. bifida
                                    25. Microsporangiate
                                        cones up to 5
                                        cm 5 cm diam.,
                                        15 cm long;
                                        median micro
                                        sporophylls
                                        apiculate
                                        with a fine
                                        spine        11. C. micholitzii

* This species, native to Japan and China, is widely cultivated
throughout Vietnam, but it is neither native nor naturalized. It
is not discussed any further in this treatment.


A. Section STANGERIOIDES Smitinand

CYCAS sect. STANGERIOIDES Smitinand, Nat. Hist. Bull. Siam. Soc. 24: 168. 1971.

TYPE SPECIES: Cycas micholitzii Dyer.

This section is defined by its soft microsporangiate cones and microsporophylls, pectinate megasporophyll apices, glabrous ovules, and seeds with a nonfibrous sarcotesta and a rugose sclerotesta. It is a taxonomically complex group, circumscribed as by Hill (1995), rather than Smitinand (1971) or Wang (1996), although present knowledge would also suggest exclusion of the Chinese species Cycas panzhihuaensis from the section. The group encompasses most of the Chinese species and ranges from northern Thailand and northeastern Myanmar eastward through Laos, Vietnam, and southern China. Fifteen species occur in Vietnam, mostly in the north (Figs. 2, 8, 9).

[FIGURES 2, 8 & 9 OMITTED]

1. CYCAS COLLINA K. D. Hill, H. T. Nguyen & Phan K. Loc, sp. nov.

TYPE: Vietnam: Son La: Mai Son, between Hat Lot and Bac Yen, alt. 400-900 m, 5 Apr 1996, S. L. Yang 777 & H. Z Nguyen (HOLOTYPE: HN).

Inter species sectionem Stangerioidem foliis paucis, foliolis late dispositis, strobilis masculis magnis, microsporophyllis apice non spinosis, megasporophyllis reductis spinam apicalem carentibus distinguitur.

Stems 15-80 cm long, 8-13 cm diam., usually subterranean or procumbent, 2-5 leaves in crown. Leaves bright to deep green, moderately glossy, 140-330 cm long, flat (not keeled) in section (opposing pinnae inserted at 150-180[degrees] on rachis), with 110-180 pinnae, with orange tomentum shedding as leaf expands, rachis consistently terminated by paired pinnae. Petiole 70-190 cm long (40-55% of total leaf), glabrous, spinescent for 90-100% of length. Basal pinnae not gradually reducing to spines, 200-260 mm long. Median pinnae simple, strongly discolorous, 280-450 mm long, 17-3 mm wide, inserted at 80-85[degrees] to rachis, decurrent for 5-10 mm, narrowed to 2.5-4 mm at base (to 15-20% of maximum width), 15-25 mm apart on rachis, section flat, margins flat or undulate; apex softly acuminate, not spinescent; midrib raised above, flat below. Cataphylls narrowly triangular, soft, pilose, 40-80 mm long. Microsporangiate cones fusiform, cream, 20-25 cm long, 9-11 cm diam. Microsporophyll lamina soft, not dorsiventrally thickened, 12-14 mm long, 7.5-10 mm wide, fertile zone 8-10 mm long, sterile apex 3-6 mm long, deflexed, apical spine absent. Megasporophylls 10-14 cm long, brown-tomentose; ovules 2-4, glabrous; lamina ovate, 60 mm long, 30 mm wide, deeply pectinate, with 10-14 soft spines ca. 30 mm long, ca. 2 mm wide, apical spine not distinct from lateral spines. Seeds ovoid, 25-27 mm long, 18-21 mm wide; sarcotesta yellow, not pruinose; fibrous layer absent; sclerotesta lightly verrucose; spongy layer absent.

Distinguishing features: Its few leaves with widely spaced pinnae and large microsporangiate cones with rounded microsporophylls that lack any apiculus distinguish Cycas collina within a group of acaulescent taxa that have reduced megasporophylls lacking a clearly distinct apical spine (Table II). This species was referred to C. simplicipinna (below) in the past.

Distribution and habitat: Somewhat restricted in distribution, in mountainous regions mostly in Son La Province in northern Vietnam (Fig. 2), above about 500 m elevation, in evergreen or partly deciduous forests or woodlands or bamboo thickets on steep slopes of mountain ridges. Substrate varies from red clay soils on limestone to loamy soils on metasediments. This species may also be expected to occur in similar terrain in Laos, although adjacent terrain in Laos is generally of lower elevation.

A population occurring west of the townlet of Moc Chau has more numerous leaves, pinnae with slender bases, short to medium petioles, and small seeds and is interpreted as a zone of intergradation with Cycas dolichophylla, which is abundant in lower country to the east (specimens cited below).

Conservation status. A widespread species, though not occurring in large or dense populations. Although its habitat is continually being reduced, many populations remain, and it is not under any immediate threat of extinction. IUCN Red List status VU A2c.

Etymology: From the Latin collinus, pertaining to hills, from the occurrence in high ridge country.

Selected specimens examined: VIETNAM. Son La: Moc Chau, Chieng Hac, Chieng Pan (21[degrees]54'17" N, 104[degrees]29'53" E), alt. ca. 500 m, 21 Mar 1999, Hill 5060 & Loc (HN, NSW); Yen Chau, Chieng Don, Chieng Dong pass (21[degrees]07'29" N, 104[degrees]12'25" E), alt. ca. 800-900 m, 21 Mar 1999, Hill 5061 & Loc (HN, NSW); Thuan Chau, Chieng Pac, Phang pass, 21 km from Son La (21[degrees]22'51" N, 103[degrees]46'26" E), alt. ca. 800-900 m, 22 Mar 1999, Hill 5062 & Loc (HN, NSW); Thuan Chau, Phong Lai (21 [degrees]32'07" N, 103[degrees]36'45" E), alt. ca. 800-900 m, 22 Mar 1999, Hill 5063 & Loc (HN, NSW); Mai Son, between Hat Lot and Bac Yen, alt. 400-900 m, Yang 778 & Hiep, 5 Apr 1996 (HN).

Intergrading population: Cycas collina x Cycas dolichophylla

VIETNAM. Son La: Moc Chau, Moc Chau townlet, 14th village (20[degrees]52'01" N, 104[degrees]35'25" E), W of Moc Chau, cult. in gardens, coll. from 3 km to SW and 1 km to N, 21 Mar 1999, Hill 5058, 5059 & Loc (HN, NSW).

2. CYCAS FUGAX K. D. Hill, H. T. Nguyen & Phan K. Loc, sp. nov. (Fig. 3).

[FIGURE 3 OMITTED]

TYPE: Vietnam: Phu Tho: Phong Chau, Tram Than, Lam, alt. 400-900 m, H. T. Nguyen 4112 & K. D. Hill, 13 Jan 2000 (HOLOTYPE: HN; ISOTYPE: NSW).

Inter species sectionem Stangerioidem foliis paucis, foliolis late dispositis, foliolis latis ad bases angustas graduatim contractis, strobilis masculis parvis, microsporophyllis apice spinosis, megasporophyllis reductis spinam apicalem carentibus et spinis lateralibus elongatis distinguitur.

Stems acaulescent, flask shaped, wholly subterranean, ca. 18 cm long, 15 cm diam. at base, 10 cm diam. at apex, larger and branched in some older plants, 1-3 leaves in crown. Leaves bright to deep green, moderately glossy, 280-380 cm long, flat (not keeled) in section (opposing pinnae inserted at 160-180[degrees] on rachis), with 80-100 pinnae, with orange tomentum shedding as leaf expands, rachis consistently terminated by paired pinnae. Petiole 150-220 cm long (50-50% of total leaf), glabrous, spinescent for 90-100% of length. Basal pinnae not gradually reducing to spines, 120-300 mm long. Median pinnae simple, strongly discolorous, 400-500 mm long, 18-27 mm wide, inserted at 70-85[degrees] to rachis, decurrent for 5-10 mm, narrowed to 2-3 mm at base (to 10-15% of maximum width), 30-40 mm apart on rachis, section flat, margins flat or undulate; apex softly acuminate, not spinescent; midrib raised above, flat below. Cataphylls narrowly triangular, soft, pilose, 30-50 mm long. Microsporangiate cones fusiform, cream, 10-12 cm long, 2.5-4 cm diam. Microsporophyll lamina soft, not dorsiventrally thickened, 12-14 mm long, 7.5-10 mm wide, fertile zone 8-10 mm long, sterile apex 3-6 mm long, deflexed, apical spine slender, closely appressed, 2-4 mm long. Megasporophylls 20-25 cm long, brown-tomentose; ovules 2-4, glabrous; lamina ovate, 110-130 mm long, 35-40 mm wide, deeply pectinate, with 10-14 soft spines 50-90 mm long, 3 mm wide, apical spine not distinct from lateral spines. Seeds ovoid, 25-27 mm long, 18-21 mm wide; sarcotesta yellow, not pruinose; fibrous layer absent; sclerotesta verrucose; spongy layer absent.

Distinguishing features: Its few, very long leaves with few, widely spaced pinnae with very narrow, tapering bases, small microsporangiate cones with microsporophylls that possess a distinct apiculus, and elongated teeth on its megasporophylls distinguish Cycasfugax within a group of acaulescent taxa that have megasporophylls lacking a clearly distinct apical spine (Table II). This species was referred to C. simplicipinna in the past.

Distribution and habitat: Known only from Phu Tho Province in northern Vietnam (Fig. 2), at about 200 m elevation. Originally growing in closed evergreen forests on low hills of orange-brown alluvial loam. Almost all of this forest on this substrate has been cleared for tea, eucalypt, and Acacia plantations.

Conservation status: Apparently a very rare and restricted species, known only from a severely threatened habitat. This species must be regarded as critically endangered and urgently in need of both close study to evaluate the conservation status and protective measures. IUCN Red List status DD/CR?

Etymology: From the Latin fugax, fleeting or ephemeral, referring to the near extinction of this species before it was recognized as a botanical entity.

Selected specimens examined: VIETNAM. Phu Tho: Phong Chau, Tram Than (21[degrees]39'27" N, 105[degrees]13'25" E), cult. in garden, said to be coll. nearby, 26 Mar 1999, Hill 5070, 5071, 5072 & Loc (HN, NSW); cult. in Phu Tho, 31 Mar 1996, Yang 775 & Hiep (HN).

3. CYCAS SIMPLICIPINNA (Smitinand) K. D. Hill, Proc. Third Int. Conf. Cycad Biol.: 150. 1995. Cycas micholitzii var. simplicipinna Smitinand, Nat. Hist. Bull. Siam Soc. 24: 164, figs. 2-3, 4f. 1971.

TYPE: Thailand: Chiang Mai Province, Doi Suthep, alt.1100 m, 19 Jul 1958, Smitinand 4757 (LECTOTYPE: BKF fide Hill, 1995).

Cycas immersa non Craib, sensu Suvatabandhu (1961).

Cycas tonkinensis, in part, sensu de Laubenfels and Adema (1998).

Literature: Smitinand (1972).

Illustrations: Smitinand (1971); Wang (1996).

Stems acaulescent, 8-14 cm diam. at narrowest point, subterranean or procumbent, 2-5 leaves in crown. Leaves bright to deep green, highly glossy, 90-250 cm long, flat (not keeled) in section (opposing pinnae inserted at 160-180[degrees] on rachis), with 35-90 pinnae, with orange tomentum shedding as leaf expands; rachis consistently terminated by paired pinnae. Petiole 35-140 cm long (40-60% of total leaf), glabrous, spinescent for 60-100% of length. Basal pinnae not gradually reducing to spines, 120-300 mm long. Median pinnae simple, strongly discolorous, 200-500 mm long, 14-20 mm wide, inserted at 50-65[degrees] to rachis, decurrent for 5-10 mm, narrowed to 2.5-4 mm at base (to 15-30% of maximum width), 20-40 mm apart on rachis; section flat; margins flat or undulate; apex softly acuminate, not spinescent; midrib raised above, flat below. Cataphylls narrowly triangular, soft, pilose, 40-50 mm long, articulated. Microsporangiate cones fusiform, cream, 15-21 cm long, 2.2-4 cm diam. Microsporophyll lamina soft, not dorsiventrally thickened, 12-14 mm long, 7.5-10 mm wide, fertile zone 8-10 mm long, sterile apex 3-5 mm long, raised, apical spine absent. Megasporophylls 7-12 cm long, brown-tomentose; ovules 2, glabrous; lamina ovate, 45-55 mm long, 18-35 mm wide, deeply pectinate, with 10-14 soft spines 15-25 mm long, 1.5-2 mm wide, apical spine not distinct from lateral spines. Seeds ovoid, 25-27 mm long, 18-21 mm wide; sarcotesta yellow, not pruinose; fibrous layer absent; sclerotesta verrucose; spongy layer absent.

Distinguishing features: Its almost totally subterranean habit with a very sparse crown of large, erect leaves with few, broad, and well-spaced pinnae, small microsporangiate cones, small megasporophylls with short spines on the apical lamina, and small seeds distinguish this species within the group of acaulescent species occurring in the Indochina region (Section Stangerioides).

Distribution and habitat: Known from western Quang Tri Province only in Vietnam (Fig. 2). Widely distributed in the mountains in northern Thailand, only above about 600 m elevation, usually in wetter and more sheltered sites in deep shade in tall, closed evergreen forests. This species also occurs in northern Myanmar and Laos. Individuals are usually scattered and sporadic in occurrence, and dense stands are uncommon.

Conservation status: A very widespread species, though not occurring in large or dense populations. Although its habitat is continually being reduced, many populations remain across a wide range (from north central Vietnam to northwestern Thailand and nearby Myanmar), and it is not under any immediate threat of extinction.

Selected specimens examined: VIETNAM. Quang Tri: Lao Bao, cult., coll. nearby, 21 Jan 2000, Hiep 4130 & Hill (HN, NSW).

THAILAND. Chiang Mai: Doi Suthep, Kerr 3206, 17 May 1914 (BM, K); Doi Inthanon, Kerr 5347, 4 May 1921 (BM, K); Chiang Mai, Kerr 5645, 13 Aug 1921 (BM, K); Phong Pho, 12 km N of Doi Chiang Dao, Larsen, Santisuk & Warncke 2859, 30 Jul 1968 (BKF); Inthanon National Park, Phengklai et al. 6749 (BKF). Loei: Khao Kating, Phu Kradung, Abbe, Abbe & Smitinand 9473, 13 Jan 1960 (BKF, L). Mae Hong Song: Nam Tok Phasua, N of Mae Hong Song, Hill 4637, 26 Apr 1994 (NSW). Phrae: Mae Sai, Winit 1686, 28 Mar 1926 (K).

LAOS. Louang Prabang, Pottier 71A (P); Phouiou Yhouan, Pottier 57B (P); Nam Minh, Pedrono 87 (P).

MYANMAR. Reported by plant collectors in northern Thailand; no voucher.

4. CYCAS BALANSAE Warb., Monsunia 1: 179. 1900. Cycas siamensis subsp. balansae (Warb.) Schuster, Pflanzenr. 99: 81. 1932.

LECTOTYPE (here designated): Tonkin (Vietnam), Hanoi, Mar 1889, B. Balansa 4084 (LECTOTYPE, see below: P; ISOLECTOYPES: G-DC, G, K).

Cycas shiwandashanica H. T. Chang & Y. C. Zhong, Chinese Bull. Bot. 12: 12. 1995. TYPE: Guangxi: Nasuo, Fangchenggang City, in broad-leaved forest, Y. C. Zhong 88015, 30 Jul 1990 (HOLOTYPE: GXF; ISOTYPES: PE, SYS).

Cycaspalmatifida H. T. Chang, Y. Y. Huang & Y. C. Zhong, Acta Sci. Nat. Univ. Sunyatseni 37: 7. 1998. TYPE: China: Guangxi: cult. in Nanning Arboretum, H. X. Zheng & Y. Y. Huang 98002, 19 Apr 1998 (HOLOTYPE: SYS).

Cycas tonkinensis, in part, sensu de Laubenfels and Adema (1998).

Literature. Chen and Stevenson (1999).

Illustrations: Cheng et al. (1975), as Cycas siamensis; Wang (1996), and as Cycas shiwandashanica.

Stems acaulescent, 12-20 cm diam. at narrowest point, 4-9 leaves in crown. Leaves deep green, highly glossy to semiglossy, 12-260 cm long, slightly keeled to flat in section (opposing pinnae inserted at 160-180[degrees] on rachis), with 90-160 pinnae, with dark brown tomentum shedding as leaf expands or persistent on petiole, rachis consistently terminated by paired pinnae. Petiole 40-160 cm long (30-40% of total leaf), pubescent with dark purple-brown tomentum, spinescent for 100% of length. Basal pinnae not gradually reducing to spines, 90-210 mm long. Median pinnae simple, strongly discolorous, 220-300 mm long, 10-15 mm wide, inserted at 75-85[degrees] to rachis, decurrent for 5-8 mm, narrowed to 3-4 mm at base (to 25-35% of maximum width), 11-21 mm apart on rachis, section flat; margins flat or slightly recurved, apex softly acuminate; not spinescent, midrib raised above, flat below. Cataphylls narrowly triangular, soft, pilose, 60-70 mm long. Microsporangiate cones fusiform, yellow, 20-25 cm long, 4-7 cm diam. Microsporophyll lamina soft, not dorsiventrally thickened, 16-30 mm long, 11-14 mm wide, fertile zone 14-28 mm long, sterile apex 2-4 mm long, level, apical spine absent. Megasporophylls 8-12 cm long; brown-tomentose; ovules 2-4, glabrous; lamina ovate, 40-50 mm long, 30-55 mm wide, deeply pectinate, with 14-24 soft spines 25-40 mm long, 2-3 mm wide, apical spine not distinct from lateral spines. Seeds ovoid, 25-27 mm long, 20 mm wide, sarcotesta yellow, not pruinose, 2 mm thick; fibrous layer absent; sclerotesta lightly verrucose; spongy layer absent.

Typification: Described by the German botanist Otto Warburg in 1900. A single collection was cited as "Im Herbarium Barbey finde ich von Balansa sub Nr 4084 gesammelte [??] Zapfen aus Tongking, nahe Hanoi aus einem Tempelhof stammend." Warburg types were mostly held by B, and Schuster (1932) cited a specimen probably from B that would probably have been the type: "Tongking: Village du papier bei Hanoi, im Hof einer Pagode (B. Balansa IV. 1889, n. 4084)." This specimen was evidently destroyed in World War II. The specimens in G, K, and P were not annotated by Warburg or Schuster and may not have been seen by either. Most of these specimens are of microsporangiate cone material only, although the material held in P comprises two sheets, one microsporangiate cone portion and one leaf portion. The microsporangiate cone sheet is annotated "B. Balansa--Pl. du Tonkin--1885-1889/Nr. 4084/Dioique. Frondes de deux metres de hauteur/Tongking: Village du papier pres de Hanoi, dans la/cour d'une pagode/Avril 1889" [Dioecious. Fronds 2 m high. Paper village near Hanoi, in the garden of a pagoda]. The two sheets held in P are here designated the lectotype.

Distinguishing features." This species is one of the complex of closely related, mostly acaulescent taxa that is distributed through northern Vietnam, Laos, northern Thailand, and Yunnan and Guangxi in southern China (Section Stangerioides). It is distinguished by its few long

leaves with long petioles bearing long, slender spines and its deep purple-brown tomentum that is often persistent. Microsporangiate cones are intermediate in size, with rounded microsporophylls that lack any apiculus. Megasporophylls are reduced, with a few long and slender divisions on the lamina. Seeds are small.

Distribution and habitat: Locally frequent though not in dense stands, in more sheltered sites in deep shade in tall, closed evergreen forests, in the region northwest and northeast of Hanoi (Lang Son, Vinh Phuc, Thai Nguyen, and Quang Ninh) and extending into the Shiwandashan (mountains) in coastal southeastern Guangxi Province of China (Fig. 2). On loamy soils over schists or granites.

Conservation status: Not considered to be at risk. IUCN Red List status LRnt.

Selected specimens examined: VIETNAM. Hai Phong: jardins a Hai Phong, 1885, Balansa 563 (P). Ha Nam: Ke So, forte ex montibus Kien Khe, 25 May 1889, Bon 4146 (P). Lang Son: Dinh Lap, Dinh Lap townlet (21[degrees]32'25" N, 107[degrees]06'32" E), 12 Mar 1999, Hill 5026, Loc & Dzu (HN, NSW); Dinh Lap, Bac Lang, Ban Ha, 27 Mar 1996, Yang & Hiep 763 (HN); Phu Son, Bac Son, Na Danh, 27 Mar 1996, Yang & Hiep 765 (HN). Quang Ninh: Hoanh Bo, Tan Dan, Hang Tran (21[degrees]08'17" N, 106[degrees]52'50" E), 11 Mar 1999, Hill 5022, 5023, Loc & Dzu (HN, NSW); Tien Yen, Dien Xa, Na Tru (21[degrees]22'47" N, 107[degrees]17'32" E), 12 Mar 1999, Hill 5025, Loc & Dzu (HN, NSW); Cam Pha, 26 Mar 1996, Yang & Hiep 758 (HN); Quang Nghia, Quang Ha, 27 Mar 1996, Yang & Hiep 761 (HN); Hai Lang, Tien Yen, 25 Mar 1996, Yang & Hiep 767 (HN). Thai Nguyen: Dai Tu, Ky Phu, Xom Gio, 19 Jan 2000, Hiep 4117 & Hill (HN, NSW). Tuyen Quang: Son Duong, Son Nam, cult. in restaurant, coll. from NW side of Tam Dao range, Tam Dao, Dai Dinh, Den Thong, 17 Mar 1999, Hill 5048 & Loc (FIN, NSW).

CHINA. Guangxi: Cult. on grounds of Nanning Forestry Research Center, Nanning (type plant of Cycas palmatifida), coll. from Fangcheng County, Chen, Zhong & Hill 01, 7 Nov 1998 (NSW, PE); cult. in Ping Mu village, Na Suo town, Fangcheng County, Guangxi Province, coll. from Fang Chen Shang Yue reserve (21[degrees]45'34" N, 108[degrees]05'33" E), alt. 240 m, Chert, Zhong & Hill 28, 19 Nov 1998 (NSW, PE).

5. CYCAS ACULEATA K. D. Hill & H. T. Nguyen, sp. nov.

TYPE: Vietnam: Da Nang: Hai Van pass, lower on S side, H. T. Nguyen 4156 & K. D. Hill, 23 Jan 2000 (HOLOTYPE: HN; ISOTYPE: NSW).

A Cycade balansaefoliis numerosioribus, petiolis longioribus, foliolis longioribus latioribusque parum carinatis basi angustioribus, cataphyllis longioribus differt.

Stems acaulescent, 15-18 cm diam. at narrowest point, 6-23 leaves in crown. Leaves deep green, highly glossy or semiglossy, 180-250 cm long, slightly keeled (opposing pinnae inserted at 130-170[degrees] on rachis), with 100-150 pinnae, with orange tomentum shedding as leaf expands; rachis consistently terminated by paired pinnae. Petiole 60-110 cm long (35-50% of total leaf), glabrous or pubescent, spinescent for 100% of length. Basal pinnae not gradually reducing to spines, 260-380 mm long. Median pinnae simple, strongly discolorous, 350-520 mm long, 13-19 mm wide, inserted at 45-60[degrees] to rachis, decurrent for 4-6 mm, narrowed to 2-3 mm at base (to 10-20% of maximum width), 15-28 mm apart on rachis; section slightly keeled; margins flat; apex softly acuminate, not spinescent; midrib raised above, flat to raised below. Cataphylls narrowly triangular, soft, pilose, 80-100 mm long, persistent. Microsporangiate cones narrowly ovoid or fusiform, 15-20 cm long, 4-6 cm diam. Microsporophyll lamina soft, not dorsiventrally thickened, 22-25 mm long, 12-14 mm wide, fertile zone 20-22 mm long, sterile apex 2-3 mm long, level, apical spine absent. Megasporophylls and seeds not seen.

Ditinguishing features: This species is one of the complex of closely related, mostly acaulescent taxa that is distributed through northern Vietnam, Laos, northern Thailand, and Yunnan and Guangxi in southern China (Section Stangerioides). It is distinguished by its few, long leaves with long petioles bearing long, slender spines and its light orange-brown tomentum. Microsporangiate cones are small, with rounded microsporophylls that lack any apiculus. It is most similar to Cycas balansae, differing in its more numerous leaves with relatively longer petioles, light orange-brown tomentum, longer and wider, slightly keeled pinnae that are more narrowed at the base, and longer cataphylls.

Distribution and habitat: Known at present from a single site on the southern slopes of the range at Hai Van pass, in dense bamboo, shrub, and grass regrowth after forest clearing (Fig. 2). Forests in the vicinity were severely affected by herbicide spraying during the north-south war in the early 1970s. It is locally frequent on loamy soils over granite on steep slopes, but the extent of the occurrence is unknown.

Conservation status: Although very poorly known to date, it is likely that this species is more widespread in the surrounding hills, IUCN Red List status DD, possibly VU.

Etymology: From the Latin aculeatus, prickly, in reference to the prominent spines on the petiole.

Selected specimens examined: VIETNAM. Cult: Cau Hai, in garden in village, coll. from Hai Van pass, Hiep 4133 & Hill, 22 Jan 2000 (HN, NSW).

6. CYCAS TANQINGII D. Yue Wang, Cycads of China: 134. 1996. (Fig. 4).

[FIGURE 4 OMITTED]

TYPE: China: Yunnan: Luchun County, D. Y. Wang 5538 (HOLOTYPE: SZG; ISOTYPE: NF n.v.).

Illustrations: Wang (1996).

Stems arborescent or acaulescent, to 2 m tall, 25-30 cm diam. at narrowest point, 4-7 leaves in crown. Leaves deep green, highly glossy, 190-360 cm long, flat (not keeled) in section (opposing pinnae inserted at 170-180[degrees] on rachis), with 100-160 leaflets, with orange tomentum shedding as leaf expands; rachis consistently terminated by paired leaflets. Petiole 70-190 cm long (40-50% of total leaf), petiole glabrous, spinescent for 90-100% of length. Basal leaflets not gradually reducing to spines. Median leaflets simple, strongly discolorous, 300-450 mm long, 15-22 mm wide, narrowed to 5-6 mm at base (to 20-30% of maximum width), inserted at 65-85[degrees] to rachis, 15-27 mm apart on rachis; section flat; margins slightly recurved; apex aristate, not spinescent; midrib raised above, raised below. Cataphylls narrowly triangular, soft, pilose to densely floccose, persistent, 50-80 mm long. Microsporangiate cones fusiform, yellow to orange, 40 cm long, 5-8 cm diam. Microsporophyll lamina soft, not dorsiventrally thickened, 25-30 mm long, 10-13 mm wide, fertile zone 22-28 mm long, sterile apex 2-3 mm long, level to raised, apical spine slender, appressed, sharply upturned, 1.5-2 mm long. Megasporophylls 10-12 cm long, brown-tomentose; ovules 2, glabrous; lamina orbicular, 50-55 mm long, 50-65 mm wide, deeply pectinate, with 6-9 soft spines 15-40 mm long, 1-3 mm wide, apical spine not distinct from lateral spines, 20-45 mm long, 7-30 mm wide at base. Seeds subglobose to ovoid, 35-40 mm long, 30-35 mm wide; sarcotesta yellow, not pruinose, 2 mm thick; fibrous layer absent; sclerotesta verrucose; spongy layer absent.

Distinguishing features: Its robust habit with a stout, aerial trunk, large microsporangiate cones, and seeds distinguish this species within Section Stangerioides. Cycas tanqingii appears to be nearest to C. dolichophylla, differing in its longer and more widely spaced pinnae that are not broad-based and rounded at the base and its longer petioles.

Distribution and habitat: Remote and mountainous country in southeastern Yunnan Province, China, possibly also across the border in Vietnam, in closed evergreen forest.

Conservation status: Unknown.

Selected specimens examined: VIETNAM. Lai Chau: reported by forestry workers from Luchun County, China, to occur on Vietnamese side of the Hejiang [river], no voucher.

CHINA. Yunnan: Luchun County, Xaio Hejiang District, Ping He, Hong 355, 356, 357, Chen, Hill & Stevenson, 9 Jul 2000 (YUN, NSW, NY, PE).

7. CYCAS CHEVALIERI Leandri, in Lecomte, Fl. Indo-Chine 5(10): 1092. 1931.

LECTOTYPE (here designated): Vietnam. Nghe An Prov., Nghia Dan, Nghia Hung (Tram Lui), 20 May 1841, F. Fleury sub. A. Chevalier 32612 (LECTOTYPE, see below: P).

Cycas tonkinensis, in part, sensu de Laubenfels and Adema (1998).

Stems arborescent or acaulescent, developing an elongate, often decumbent, stem with age, to 1.2 m tall, 8-18 cm diam. at narrowest point, 4-15 leaves in crown. Leaves deep green, highly glossy, 130-240 cm long, slightly keeled to flat in section (opposing pinnae inserted at 150-180[degrees] on rachis), with 80-110 pinnae, with orange or brown tomentum shedding as leaf expands, rachis consistently terminated by paired pinnae. Petiole 70-140 cm long (45-60% of total leaf), glabrous, unarmed or spinescent for up to 100% of length. Basal pinnae not gradually reducing to spines, 170-240 mm long. Median pinnae simple, strongly discolorous, 250-420 mm long, 14-20 mm wide, inserted at 50-80[degrees] to rachis, decurrent for 2-6 mm, narrowed to 2.5-4 mm at base (to 15-30% of maximum width), 15-21 mm apart on rachis; section flat, margins flat or undulate, apex softly acuminate, not spinescent; midrib raised above, raised below. Cataphylls narrowly triangular, soft, pilose, 50-70 mm long. Microsporangiate cones fusiform, brown or cream, 15-25 cm long, 4-7 cm diam. Microsporophyll lamina soft, not dorsiventrally thickened, 14-17 mm long, 7-10 mm wide, sterile apex raised, apical spine absent. Megasporophylls 9-13 cm long, brown-tomentose; ovules 2-4, glabrous; lamina orbicular, 35-55 mm long, 25-50 mm wide, deeply pectinate, with 15-25 soft lateral spines 20-35 mm long; apical spine sometimes distinct from lateral spines, 25-40 mm long, 3-8 mm wide at base. Seeds ovoid, 18-27 mm long, 15-25 mm wide; sarcotesta yellow, not pruinose, 1-2 mm thick; fibrous layer absent; sclerotesta verrucose; spongy layer absent.

Typification: Two collections were cited, as follows: "Tonkin occidental: (Ckevalier).--Nord-Annam: prov. de Nghe-an (Vinh), delegation de Nghia-hung a Tram-lui (Chevalier)." Only the second specimen (Chevalier 32612) appears to remain, and it is here designated the lectotype.

Historical notes. Published by the French botanist J. D. Leandri in 1931, this name was ignored by Ho in his general enumerations of Vietnamese plants (Ho & Duong 1960; Ho 1991). Cycas chevalieri was placed in the synonymy of the related C. balansae by Hiep & Vidal (1996) but is now recognized as a distinct species more closely allied to C. hoabinhensis than to C. balansae. This species was largely unknown except for the type collections until recollected in 1998. The original type locality was by this time cleared for cultivation and had been previously searched for C. chevalieri, in vain. The recent discovery of large numbers of plants was made some 120 km to the south, in relatively undisturbed forest in the foothills of the Annam Highlands. Subsequent field studies have extended the range south to Khe Sanh in Quang Tri and show this to be a widespread and abundant species.

Distinguishing features: Within a complex of closely related, mostly acaulescent taxa (Section Stangerioides), this species is distinguished by its medium stature, broad pinnae, long petioles relative to total leaf length, erect petioles with short spines that are not usually continued onto the swollen leaf base, reflexed leaf blade, small megasporophylls lacking a clearly distinct apical spine, and small microsporangiate cones with a slender apical spine on its microsporophyll. Older plants develop a slender, often decumbent, aerial trunk.

Distribution and habitat: Locally abundant in tall, closed evergreen forest on sandy loams over schists and granites in the region inland from Vinh and Ha Tinh and south to Khe Sanh, in mountain foothills in Nghe An, Ha Tinh, Quang Binh and Quang Tri Provinces (Fig. 2). This species often grows in boulder beds along riverbanks, where it may form large, multiheaded clusters.

Conservation status: Not considered to be at risk. Very large populations occur in well-preserved forest. IUCN Red List status LRnt.

Selected specimens examined: VIETNAM. Ha Tinh: Huong Son, Son Kim, Rao An (18[degrees]22'34" N, 105[degrees]13'07" E), 13 May 1998, Hill 5004, 5005, 5006 & Loc (NSW, HN, K, NY, PE, BKF, L). Nghe An: Dien Chau, Dien Lain, 29 Oct 1994, Hiep & Yang 2019 (HN); Yang & Hiep SLY530 (HN). Quang Tri: Dak Rong, Cu Poho, Rao Quan River, 21 Jan 2000, Hiep 4126 & Hill (HN, NSW).

8. CYCAS HOABINHENSIS Phan K. Loc & H. T. Nguyen, sp. nov. (Fig. 5).

[FIGURE 5 OMITTED]

TYPE: Vietnam: Hoa Binh: Lac Thuy, Chi Ne, Jul 1966, Phan K. Loc P3194a (HOLOTYPE: HNU; ISOTYPE: HN, NSW).

Inter species sectionem Stangerioidem statura parva, foliis paucis brevibus, foliolis paucis latis, strobilis masculis parvis, microsporophyllis apice spiniferis, megasporophyllis reductis spinam apicalem carentibus et spinis lateralibus reductis distinguitur

Stems arborescent or acaulescent, to 0.6 m tall, 5-8 cm diam. at narrowest point, 2-10 leaves in crown. Leaves bright green, highly glossy, 50-130 cm long, flat (not keeled) in section (opposing pinnae inserted at 170-180[degrees] on rachis), with 40-100 pinnae, with white tomentum shedding as leaf expands, rachis consistently terminated by paired pinnae. Petiole 25-60 cm long (40-60% of total leaf), glabrous, spinescent for 100% of length, basal pinnae not gradually reducing to spines, pinnae 150-250 mm long. Median pinnae simple, strongly discolorous, 200-280 mm long, 11-21 mm wide, inserted at 60-80[degrees] to rachis, decurrent for 2-4 mm, narrowed to 2.5-5 mm at base (to 15-30% of maximum width), 15-20 mm apart on rachis, section flat, margins flat or undulate, apex softly acuminate, not spinescent; midrib raised above, raised below. Cataphylls narrowly triangular, soft, pilose, 50-70 mm long. Microsporangiate cones narrowly ovoid or fusiform, yellow, 10-12 cm long, 5-6 cm diam. Microsporophyll lamina soft, not dorsiventrally thickened, 22 mm long, 10 mm wide; fertile zone 20 mm long, sterile apex 2 mm long, raised, apical spine distinct or rudimentary, appressed, sharply upturned, 4-10 mm long. Megasporophylls 7 cm long, brown-tomentose; ovules 2-4, glabrous; lamina orbicular, 30 mm long, 20 mm wide, deeply pectinate, with ca. 10 soft spines ca. 20 mm long, ca. 2.5 mm wide, apical spine not distinct from lateral spines. Sarcotesta yellow, not pruinose; fibrous layer absent; sclerotesta verrucose; spongy layer absent.

Historical notes: Though an abundant species occurring naturally near the large city of Hanoi and very popular as a horticultural subject in that city in recent years, this was not recognized as a distinct species until 1996-1998, when field studies permitted the true complexity of the taxonomy of the northern Vietnamese cycads to become clearer.

Distinguishing features: Within a complex of closely related, mostly acaulescent taxa (Section Stangerioides), this species is distinguished by its very small stature, small megasporophylls lacking a clearly distinct apical spine, and slender apical spine on the microsporophyll. It is nearest to Cycas chevalieri and C. brachycantha, both of which share its small megasporophyll but are otherwise larger in stature. Older plants develop a short, very slender, often twisted or decumbent, aerial trunk.

Distribution and habitat: Locally abundant, in somewhat sheltered sites on steep limestone outcrops, usually within the canopy of closed evergreen forest on ridge crests in the region south of Hanoi (Fig. 2). The habitat is the same as that of the closely related Cycas brachycantha from north of Hanoi.

Conservation status: This species has been extensively exploited for the ornamental plant trade in Hanoi, severely depleting many of the more accessible populations. Although large populations remain in relatively inaccessible areas, the extensive depletion to date (and continuing) is cause for concern, and this species must be regarded as threatened. IUCN Red List status EN A2c.

Etymology." From the occurrence in Hoa Binh Province, northern Vietnam, with the Latin termination -ensis, place of origin.

Selected specimens examined: VIETNAM. Ha Nam: Kim Bang, Ba Sao, Mar 1996, Binh s.n. (HN); cult. in Dien Binh, Gia Lam District, Hanoi, plant coll. from Than Liem District (ca. 20[degrees] 27' N, 106[degrees]02, E), 11 May 1998, Hill 5003 & Loc (NSW, HN, K). Ha Tay: Chua Huong, 21 Mar 1996, Yang & Hiep SLY757 (HN). Hoa Binh: Luong Son, 22 Oct 1994, Yang & Hiep SLY519 (HN); Lac Thuy, Chi Ne, 24 Oct 1994, Yang & Hiep SLY425 (HN). Ninh Birth: Cuc Phuong, 15 Jun 1995, Hiep 2056 (HN); Nho Quan, Cuc Phuong Cuc Phuong National Park, ridge crest near gate (20[degrees]15'54" N, 105[degrees]41 '48" E), 18 Mar 1999, Hill 5050 & Loc (HN, NSW).

9. CYCAS BRACHYCANTHA K. D. Hill, H. T. Nguyen & Phan K. Loc, sp. nov. (Fig. 6).

[FIGURE 6 OMITTED]

TYPE: Vietnam: Bac Can: Ba Be, Hin Dan Mountain, H. T. Nguyen 4119 & K. D. Hill, 17 Jan 2000 (HOLOTYPE: HN; ISOTYPE: NSW).

Inter species sectionem Stangerioidem statura modica, foliis paucis, strobilis masculis omnino parvis, pedunculo longo, microsporophyllis apice non spinosis, megasporophyllis reductis spinam apicalem carentibus et spinis lateralibus elongatis distinguitur.

Stems 0-1 m tall, 9-12 cm diam., 5-10 leaves in crown. Leaves deep green, highly glossy, 140-250 cm long, slightly keeled to flat (not keeled) in section (opposing pinnae inserted at 160-180[degrees] on rachis), with 100-210 pinnae, with white tomentum shedding as leaf expands, rachis consistently terminated by paired pinnae. Petiole 50-90 cm long (35-45% of total leaf), glabrous, spinescent for 90-100% of length. Basal pinnae not gradually reducing to spines, 150-200 mm long. Median pinnae simple, strongly discolorous, 200-250 mm long, 10-14 mm wide, inserted at 70-85[degrees] to rachis, decurrent for 6-8 mm, narrowed to 2.5-4 mm at base (to 20-30% of maximum width), 10-21 mm apart on rachis, section flat, margins undulate; apex softly acuminate, not spinescent; midrib raised above, flat below. Cataphylls narrowly triangular, pungent, pilose, 50-80 mm long, articulated. Microsporangiate cones fusiform, yellow, 12-14 cm long, 3-4 cm diam. Microsporophyll lamina soft, not dorsiventrally thickened, sterile apex level, apical spine absent. Megasporophylls 8-12 cm long, brown-tomentose; ovules 2-4, glabrous; lamina ovate, 25-40 mm long, 15-25 mm wide, deeply pectinate, with 14-22 soft spines 15-25 mm long, ca. 2.5 mm wide, apical spine not distinct from lateral spines. Seeds ovoid, 25-27 mm long, 20 mm wide; sarcotesta yellow; fibrous layer absent; sclerotesta verrucose; spongy layer absent.

Historical notes: Cycas brachycantha was first discovered and recognized as a distinct species only in the late 1990s.

Distribution and habitat. Known at present from a limited region in Bac Can Province (Fig. 2). Locally frequent, though not in dense stands, on the crests of outcropping limestone ridges within closed evergreen forest canopy, growing in clefts and crevices in bare rock with little or no soil.

Distinguishing features: Its medium stature, very small microsporangiate cones on long peduncles with rounded microsporophylls that lack any apiculus, and long petioles with short spines distinguish this species. It is also part of the complex of closely related, more or less acaulescent taxa with reduced megasporophylls lacking a clearly distinct apical spine that is distributed through northern Vietnam, Laos, northern Thailand, and Yunnan and Guangxi in southern China. Older plants develop a slender, often decumbent, aerial trunk. Within this complex its reduced megasporophylls suggest that Cycas brachycantha is nearest to C. hoabinhensis and C. chevalieri.

Conservation status: Well represented within Ba Be National Park and not considered to be at risk. IUCN Red List status LRnt.

Etymology: From the Greek brachys, short, and acanthos, spine, referring to the characteristically short petiolar spines of this species.

Selected specimens examined: VIETNAM. Bac Can: Cho Don, Nam Mau, hills behind village, 15 Mar 1999, Hill 5033, 5034 & Loc (HN, NSW); cult. in village, coll. nearby, 15 Mar 1999, Hill 5035 & Loc (HN, NSW).

10. CYCAS DOLICHOPHYLLA K. D. Hill, H. T. Nguyen & Phan K. Loc, sp. nov. (Fig. 7).

[FIGURE 7 OMITTED]

TYPE: Vietnam: Tuyen Quang: Na Hang, Pu La Mountain, 2 Nov 1996, H. T. Nguyen 2124 (HOLOTYPE: HN)

Inter species sectionem Stangerioidem statura magna, trunco aerio robusto, foliis multo longioribus, petiolo brevi, foliolis latis confertis brevioribus basi abrupte contractis, strobilis masculis magnis, microsporophyllis apice non spinosis, megasporophyllis reductis spinam apicalem carentibus et spinis lateralibus elongatis distinguitur.

Stems arborescent, to 1.5 m tall, 18-30 cm diam. at narrowest point. 8-40 leaves in crown. Leaves bright green to deep green, highly glossy, 200-450 cm long, flat (not keeled) in section (opposing pinnae inserted at 180[degrees] on rachis), with 150-270 pinnae, with orange tomentum shedding as leaf expands; rachis consistently terminated by paired pinnae. Petiole 40-110 cm long (20-35% of total leaf), glabrous, spinescent for 90-100% of length. Basal pinnae not gradually reducing to spines, 90-240 mm long. Median pinnae simple, strongly discolorous, 190-420 mm long, 14-25 mm wide, inserted at 60-85[degrees] to rachis, decurrent for 5-8 mm, narrowed to 3-6 mm at base (to 20-35% of maximum width), distinctively rounded at base, 16-30 mm apart on rachis; section flat; margins undulate; apex softly acuminate, not spinescent; midrib raised above, flat below. Cataphylls narrowly triangular, soft, pilose, 80-120 mm long. Microsporangiate cones narrowly ovoid or fusiform, yellow, 35-58 cm long, 8-10 cm diam. Microsporophyll lamina soft, not dorsiventrally thickened, 30-36 mm long, 9-13 mm wide, fertile zone 27-34 mm long, sterile apex 2-4 mm long, level, apical spine rudimentary or absent, sharply upturned, 0-3 mm long. Megasporophylls 15-26 cm long, brown-tomentose; ovules 2-4, glabrous; lamina orbicular, 60-120 mm long, 50-100 mm wide, deeply pectinate, with 16-26 soft spines 40-50 mm long, 2-3 mm wide, apical spine not distinct from lateral spines. Seeds ovoid or flattened-ovoid or oblong, 40-64 mm long, 33-36 mm wide; sarcotesta yellow, not pruinose, 2-4 mm thick; fibrous layer absent; sclerotesta verrucose; spongy layer absent.

Historical notes': Though the most widespread and abundant cycad in northern Vietnam, Cycas dolichophylla was recognized as a distinct species only in the late 1990s.

Distinguishing features." Its robust, though usually short, aerial trunk, longer and more numerous leaves with more numerous pinnae that are short, broad, and distinctively rounded at the base, long, slender petiolar spines, and larger microsporangiate cones with rounded microsporophylls that lack any apiculus distinguish this species. Megasporophylls are similar to those of Cycas balansae but larger and more robust. Cycas dolichophylla is also part of the complex of closely related taxa that is distributed through northern Vietnam, Laos, northern Thailand and Yunnan and Guangxi in southern China (Section Stangerioides). Within this section, a subgroup that may be a natural group is defined by its robust habit with a stout, erect, aerial trunk. This subgroup is mainly Chinese (including C. hainanensis C. J. Chen, C. taiwaniana Carruth. and, C. diannanensis Z. T. Guan & G. D. Tao), with C. dolichophylla the only member of the group known to extend beyond China.

Distribution and habitat: Locally frequent in more sheltered sites in deep shade in tall, closed evergreen forests, from near the Chinese border in the north and northwest to Ben En National Park in Thanh Hoa Province in the south, extending northwestward to a very short way into eastern Yunnan Province (Fig. 2). This species occurs on loamy soils over limestone, shale, schist, or granite, in closed evergreen forests, although today these are often reduced to scrubby regrowth and bamboo scrub.

A population occurring west of the city of Moc Chau has narrow pinnae with slender bases, short to medium petioles, and small seeds and is interpreted as a zone of intergradation with Cycas collina, which is abundant in higher country to the west (specimens cited above under C. collina). Plants observed in cultivation around Vo Nhai and Yen Son Districts, Thai Nguyen Province, were intermediate in form between C. dolichophylla and C. ferruginea and have been interpreted as hybrid individuals. In this region, C. ferruginea is abundant on steep, exposed limestone faces, and C. dolichophylla is abundant in adjacent closed forests on deep heavy soils (specimens cited below). Plants observed in cultivation in villages west of Thai Nguyen and said to have been collected locally were morphologically intermediate between C. dolichophylla and C. bifida.

Conservation status: Not considered to be at risk. IUCN Red List status LR cd.

Etymology: From the Greek dolichos, long, and phyllon, leaf, referring to the distinctively long leaves of this species.

Selected specimens examined: VIETNAM. Bac Can: Bac Can city, cult., coll. from ca. 13 km to SE, 15 Mar 1999, Hill 5036 & Loc (HN, NSW); Cho Moi, Tan Son, Nam Dat (22[degrees]06'09" N, 105[degrees]55'00" E), alt. ca. 400 m, 16 Mar 1999, Hill 5037, 5038 & Loc (HN, NSW). Can Bang: Nguyen Binh, Huo Tham, Be Nuoc (22[degrees]33'40" N, 106[degrees]06'02" E), alt. ca. 400 m, 14 Mar 1999, Hill 5032 & Loc (HN, NSW). Ha Giang: Vi Xuyen, Viet Lam, Muc, 28 km S of Ha Giang city, cult. in village (22[degrees]37'26" N, 104[degrees]57' 18" E), coll. ca. 3 km to NW, 26 Mar 1999, Hill 5068 & Loc (HN, NSW); Vinh Tuy, SE edge of Vinh Tuy townlet (22[degrees]14'55" N, 104[degrees]56'26" E), cult. in garden, coll. ca. 20 km SW, 26 Mar 1999, Hill 5069 & Loc (HN, NSW). Lai Chart: Phong Tho, Muong So, Vang Khon, cult. in village (22[degrees]32'29" N, 103[degrees]19'21" E), coll. from steep limestone ridge behind village, 23 Mar 1999, Hill 5064 & Loc (HN, NSW); Phong Tho, Muong So, Phuong Lanh (22[degrees]31 '37" N, 103[degrees]20'46" E), 24 Mar 1999, Hill 5065 & Loc (I-IN, NSW). Lao Cai: Lao Cai city, cult., coll. 10 km to W or SW (ca. 22[degrees]21' N, 104[degrees]04' E), 24 Mar 1999, Hill 5066 & Loc (HN, NSW); Bao Yen, Thuong Ha, third village (22[degrees]16'33" N, 104o23'55" E), 25 Mar 1999, Hill 5067 & Loc (HN, NSW). Ninh Binh: Cuc Phuong, 29 Dec 1994, Hiep 2029 (HN); Nho Quan, Cuc Phuong National Park, near gate, cult. on old village site, thought to have been coll. locally, 18 Mar 1999, Hill 5049 & Loc (HN, NSW); Nho Quan, Cue Phuong National Park, near Bong (20[degrees]51'25" N, 105[degrees]35'22" E), 18 Mar 1999, Hill 5051 & Loc (HN, NSW); Nho Quan, Cuc Phuong National Park, cult. in village at entrance gate, coll. nearby, 19 Mar 1999, Hill 5052 & Loc (HN, NSW). Son La: Moc Chau, Van Ho, Hang Trung, 20 km E of Moc Chau (20[degrees]47'37" N, 104[degrees]46'32" E), 21 Mar 1999, Hill 5057 & Loc (HN, NSW). Thai Nguyen: Vo Nhai, Lau Thuong, Lung Hang, cult. near house, coll. 500 m to E (21[degrees]43'47" N, 106[degrees]00'27" E), 16 Mar 1999, Hill 5041, 5042 & Loc (HN, NSW). Thanh Hoa: Nhu Xuan, Ben En National Park, 13 Oct 1996, Hiep 2116, 2117, 2118 (HN); Nhu Thanh, Hai Van, Xuan Lai (19[degrees]36'32" N, 105[degrees]33'26" E), 19 Mar 1999, Hill 5054 & Loc (HN, NSW); Ngoc Lac, Minh Son, Minh Chau, cult. in village, coll. nearby (20[degrees]02'22" N, 105[degrees]24'13" E), 20 Mar 1999, Hill 5055 & Loc (HN, NSW); Lang Chanh, Dong Luong, Thung (20[degrees]11'42" N, 105[degrees]15'41" E), 20 Mar 1999, Hill 5056 & Loc (HN, NSW). Tuyen Quang: Chiem Hoa, Yen Nguyen, Dong Vang, 29 Mar 1996, Yang & Hiep 768 (HN); 31 Mar 1996, Yang & Hiep 774 (HN); Na Hang, Pac Ban, Nam Chang, 30 Mar 1996, Yang & Hiep 769, 770 (HN); Hiep 2083 (HN); Yen Son, Tien Bo, Goc Thi (21[degrees]44'37" N, 105[degrees]21'23" E), cult. in garden, coll. from wooded hills close by, 17 Mar 1999, Hill 5046 & Loc (HN, NSW).

CHINA. Yunnan: Hekou County, An Gia He District, cult. in Ma Chang village, brought from Yang Hui village, Hong 329, Chen, Hill & Stevenson, 4 Jul 2000 (YUN, NSW, NY, PE); Hekou County, Nan Xe Tung municipality, Xiao Xi He village, 132 dam, Hong 332, 333, Chen, Hill & Stevenson, 4 Jul 2000 (YUN, NSW, NY, PE).

Hybrid swarm: Cycas dolichophylla x Cycas ferruginea

VIETNAM. Thai Nguyen: Vo Nhai, Lau Thuong, Lang Hang, cult. near house, coll. 500 m to E (21[degrees]43'47" N, 106[degrees]00'27" E), 16 Mar 1999, Hill 5039, 5040 & Loc (FIN, NSW); Quang Son, Dong Hai, cult. in gardens (21[degrees]41'50" N, 105[degrees]53'12" E), coll. from steep limestone cliffs 300-400 m to W, 16 Mar 1999, Hill 5045 & Loc (FIN, NSW).

Hybrids." Cycas dolichophylla x Cycas bifida

VIETNAM. Thai Nguyen: 15 km NW of Thai Nguyen city--sight record, no voucher, H. T. Nguyen & K. D. Hill, 17 Jan 2000.

11. CYCAS MICHOLITZII Dyer, Gard. Chron. 38: 142-144, figs. 48-49. 1905.

TYPE: Annam, Micholitz s.n. (HOLOTYPE: K, 4 sheets).

Dyerocycas micholitzii (Dyer) Nakai, Ordines, familiae, tribi, ... et combinationes a Prof. Nakai-Takenosin adhuc novis edita 208. 1943; as mischolitzi.

Epicycas micholitzii (Dyer) de Laub., in de Laub. & Adema, Blumea 43: 389. 1998.

Literature. Leandri (1931); Ho and Duong (1960); Smitinand (1971).

Illustrations: Thiselton-Dyer (1905); Prain (1909); Raffill (1912); Smitinand (1971).

Stems acaulescent, 10-15 cm diam. at narrowest point, 2-6 leaves in crown. Leaves bright green, semiglossy or dull, 110-240 cm long, moderately keeled (opposing pinnae inserted at 90-120[degrees] on rachis), with 18-56 pinnae, with white tomentum shedding as leaf expands; rachis consistently terminated by paired pinnae. Petiole 50-105 cm long (40-55% of total leaf), petiole glabrous, spinescent for 70-95% of length. Basal pinnae not gradually reducing to spines, 230-330 mm long. Median pinnae dichotomously branched, strongly discolorous, 230-360 mm long, 11-19 mm wide, inserted at 60[degrees] to rachis, narrowed to 2-3 mm at base (to 10-20% of maximum width), 35-60 mm apart on rachis; section flat; margins flat; apex softly acuminate, not spinescent; midrib raised above, flat below. Cataphylls narrowly triangular, soft, pilose, 60-80 mm long, articulated. Microsporangiate cones narrowly ovoid or fusiform, yellow, 15-25 cm long, 3-5 cm diam. Microsporophyll lamina soft, not dorsiventrally thickened, 13-18 mm long, 7-11 mm wide, apical spine prominent or rudimentary, sharply upturned, 1-6 mm long. Megasporophylls deeply pectinate. Seeds ovoid; fibrous layer absent; sclerotesta verrucose; spongy layer absent.

Historical notes." This remarkable species was described by the English botanist Sir William Thiselton-Dyer in 1905. Material apparently collected by Micholitz in Annam (northern Vietnam), came into possession of Henry Ridley, director of Singapore Botanic Gardens, in 1904. He proposed that it should be the type of a new genus (in correspondence to Thiselton-Dyer). Thiselton-Dyer received material of Micholitz's collections from Sander & Sons in 1905 and from Ridley (including botanical drawings by an artist on Ridley's staff) at about the same time. He astutely recognized that this species belonged with the genus Cycas, despite the unusual leaf. He described it as a new species in 1905, noting the similarities with the specimen he had earlier described as Cycas rumphii var. bifida but not combining the two. Subsequent authors until now have combined the two, although closer inspection in recent times has now shown them to be distinct (see C. bifida).

Quite large numbers of plants were collected by Micholitz and imported to England by Sander & Sons, and the species created considerable interest in European horticultural circles (Prain, 1909; anon., 1910; Raffill, 1912). Male and female coning was documented at Kew (anon., 1910; Raffil, 1912), but most of the imported plants were apparently lost in the general decline in interest in exotic ornamental horticulture that followed World War I. The Dublin Botanic Gardens is the only collection known to still have a single plant from these collections (in 1998).

Distinguishing features: The most immediately striking feature of this species is its dichotomously divided pinnae. However, this also occurs in several related taxa and in a horticultural form of Cycas revoluta that is popular in Japan. Its subterranean habit, small, soft microsporangiate cones, loose, freely peeling sarcotesta lacking a fibrous layer, and verrucose sclerotesta are also all features shared by related species (Section Stangerioides). Within the group of related species with divided pinnae, C. micholitzii is distinguished by its short leaves with dull, comparatively short and narrow pinnae that are dichotomously divided very near to or at the base and its small microsporangiate cones with distinct short, slender spines on the microsporophyll tips.

Distribution and habitat: The Annam Highlands region of central Vietnam and eastern Laos, mostly in low, scrubby, but fairly dense woodland, extending into drier monsoon savanna forests (Fig. 8).

Conservation status: Virtually unknown from the time of Micholitz until the past few years, this species has been severely reduced in numbers both by collecting and by unrestrained agricultural and forestry development. The rarity, combined with the unusual habit, makes it a highly sought plant by collectors. It is still, however, frequent in many places and is not considered to be at risk in the short term. IUCN Red List status LR cd.

Selected specimens examined: VIETNAM. Dac Lac: Buon Chet, Schmidt s.n. (P), Ban Me Thuot, Schmidt 872 (P).Gia Lai: Hau Bon (Cheo Reo), Dournes s.n., Apr 1967 (P); 10 km W of An Khe, Nat. Geog. Soc. Exped VH 1461, 19 Apr 1995 (HN, P); Kong Na Nung, Ka Nae, Dzu s.n., Oct 1991 (P); An Khe, Ha Tam, 1 Nov 1994, Yang, Ban & Lindstrom SLY536 (HN). Kon Tum: Dac To, Tan Canh, 8 May 1996, Hiep 2088 (HN); Sa Thay, Ro Koy (14[degree]27'09" N, 107[degree]36'42" E), 7 Apr 2000, P .K. Loc P8568 (HN, HNU, MO).

12. CYCAS BIFIDA (Dyer) K. D. Hill, comb. nov.

BASIONYM: Cycas rumphii var. bifida Dyer, J. Linn. Soc., Bot. 26: 560. 1902.

TYPE: China: Guangxi: Lighthouse pagoda rockhills, Lungchow [Longzhou], Morse 273, Dec 1896 (HOLOTYPE: K, 2 sheets).

Literature: Cheng et al. (1975), as Cycas micholitzii; Chen and Stevenson (1999), as Cycas micholitzii.

Illustrations: Wang (1996), as Cycas micholitzii.

Stems acaulescent, 10-30 cm diam. at narrowest point, 2-5 leaves in crown. Leaves bright green, semiglossy, 200-500 cm long, slightly keeled to flat in section (opposing pinnae inserted at 120-180[degree] on rachis), with 40-80 pinnae, with white and orange tomentum shedding as leaf expands; rachis usually terminated by paired pinnae. Petiole 110-160 cm long (35-50% of total leaf), glabrous, spinescent for 90-100% of length. Basalpinnae not gradually reducing to spines. Median pinnae dichotomously branched up to three times, strongly discolorous, 300-600 mm long, 18-25 mm wide, inserted at 45-70[degrees] to rachis, decurrent for 10-15 mm, narrowed to 3-4 mm at base (to 14-20% of maximum width), 60-95 mm apart on rachis; section flat; margins flat; apex softly acuminate, not spinescent; midrib raised above, flat below. Cataphylls narrowly triangular, soft, pilose, 55-90 mm long. Microsporangiate cones fusiform, yellow or cream, 35-55 cm long, 6-8 cm diam. Microsporophyll lamina soft, not dorsiventrally thickened, 17-28 mm long, 13-16 mm wide, fertile zone 14-25 mm long, sterile apex 2-3 mm long, level, apical spine absent. Megasporophylls 7-11 cm long, brown-tomentose; ovules 24, glabrous; lamina ovate, 35-100 mm long, 25-50 mm wide, deeply pectinate, with 12-15 soft lateral spines 18-50 mm long, 2-3 mm wide, apical spine distinct or not distinct from lateral spines, 15-70 mm long, 3-8 mm wide at base. Seeds flattened-ovoid, 25 mm long, 20 mm wide; sarcotesta yellow, not pruinose, 2 mm thick; fibrous layer absent; sclerotesta verrucose; spongy layer absent.

Historical notes': This species was first recognized as a distinct taxon in Western literature by the English botanist Sir William Thiselton-Dyer in 1902, who described it as Cycas rumphii var. bifida, on the basis of a leaf fragment collected by H. B. Morse in the Longzhou District of southern Guangxi in 1896. Thiselton-Dyer later received material apparently collected by W. Micholitz in Annam (northern Vietnam) from Sander & Sons in 1905 and material from Henry Ridley of the Singapore Botanic Gardens at about the same time. He described this as a new species C. micholitzii in 1905, noting the similarities with the specimen he had earlier described as C. rumphii var. bifida but not combining the two. Subsequent authors regarded them as the same species until recent studies showed them to be distinct.

Distinguishing features: The most immediately striking feature of this species is its dichotomously divided pinnae. However, this also occurs in several related taxa and in a horticultural form of Cycas revoluta that is popular in Japan. Its subterranean habit, small, soft microsporangiate cones, loose, freely peeling sarcotesta lacking a fibrous layer, and verrucose sclerotesta are also all features shared by a wider group of related species (Section Stangerioides). Within this group of related species, C. boqda is distinguished by its long leaves with glossy, thin-textured, comparatively long and broad pinnae that are dichotomously divided very near to the base. It is most similar to C. micholitzii from central Vietnam and can be distinguished by its larger stature, longer, broader, more lax, and glossier pinnae, and larger microsporangiate cones with mostly nonspinescent microsporophylls. This species has no connection whatsoever with Cycas rumphii, a seashore species from section Cycas that occurs in Indonesia.

Distribution and habitat: Southern Guangxi Province in China and Lang Son in far northeastern Vietnam (Fig. 8). Locally abundant, but many populations are now depleted, in low, scrubby, but fairly dense mixed evergreen and deciduous or bamboo woodland, often on red terra rosa soils on and around steep, karst limestone outcrops but also on loamy soils over shales and metasandstones. This species is apparently sympatric with Cycas multipinnata in several populations in China, and a range of morphologically intermediate forms that can be interpreted as a hybrid swarm has been observed (see C. longipetiolula, excluded names, below). Hybrids are also known with C. diannanensis in China and C. dolichophylla in Vietnam. The type of C. multifrondis is thought to represent a hybrid with a simply pinnate species of unknown identity (see excluded species below).

Conservation: This species has been severely reduced in numbers both by collecting and by unrestrained agricultural and forestry development. Its rarity, combined with its unusual habit, makes it a very highly sought plant by collectors. It is still, however, frequent in many places, especially in Vietnam, and is not considered to be at risk in the short term. IUCN Red List status VU A2c.

Selected specimens examined: VIETNAM. Lang Son: Trang Dinh, Chi Lang, Keo Quang (22[degrees]17'11" N, 106[degrees]27'22" E), 13 Mar 1999, Hill 5027, Loc & Dzu (HN, NSW); Binh Gia, Thien Hoa, Thien Thua, 28 Mar 1996, Yang & Hiep SLY764 (HN). Cao Bang: Thach An, Duc Xuan, Tuc Nga (22[degrees]22'18" N, 106[degrees]26'24" E), alt. ca. 200 m, 13 Mar 1999, Hill 5028, 5030 & Loc (HN, NSW); Thach An, Tong Con, 3 Dec 1996, Loc et al. CBL853 (HN). Tuyen Quang: Son Duong, Hop Thanh, Dong Dai, Hiep 4116 & Hill, 15 Jan 2000 (HN, NSW); Yen Son, Tien Bo, Goc Thi, cult. in garden, coll. from wooded hills in general vicinity (21[degrees]44'37" N, 105[degrees]21'23" E), 17 Mar 1999, Hill 5047 & Loc (HN, NSW).

CHINA. Guangxi: cult. in nursery of Nanning Forestry Research Center, Nanning, coll. Longzhou County, 7 Nov 1998, Chert, Zhong & Hill 3 (NSW, PE); cult. in Longzhou city park, coll. Longzhou County, 21 Nov 1998, Chen, Zhong & Hill 35 (NSW, PE). Yunnan: Hekou County, Hong 347, Chen, Hill & Stevenson, 6 Jul 2000 (YUN, PE).

Hybrids: Cycas multifrondis x Cycas multipinnata

CHINA. Yunnan: Gejiu County, Yuanjiang River valley, D. Y Wang & H. Peng 5523, 23 Apr 1994 (SZG; holotype of Cycas longipetiolula). Hekou County, Hong 350, Chen, Hill & Stevenson, 6 Jul 2000 (YUN, PE).

13. CYCAS MULTIPINNATA C. J. Chen & S. Y. Yang, Acta Phytotax. Sin. 32: 239. 1994.

TYPE: China: Yunnan: S. Jianshui County, near Red River, alt. 1100 m, Apr 1987, S. Y Yang 9202 (HOLOTYPE: PE).

Epicycas multipinnata (Chen & Yang) de Laub., in de Laub. & Adema, Blumea 43: 391. 1998.

Literature: Wang (1996); Chen and Stevenson (1999).

Illustrations: Wang (1996), and as Cycas longipetiolula.

Stems acaulescent, 14-25 cm diam. at narrowest point, 1-2 leaves in crown. Leaves deep green, highly glossy, 200-600 cm long, slightly keeled (opposing pinnae inserted at 120-150[degrees] on rachis), bipinnate, with 14-36 pinnae, with white tomentum shedding as leaf expands; rachis consistently terminated by paired pinnae. Petiole 100-350 cm long (50-65% of total leaf), glabrous, spinescent for 90-100% of length. Basalpinnae not gradually reducing to spines, 500-720 mm long. Median pinnae pinnately divided, strongly discolorous, 400-600 mm long, inserted at 45-70[degrees] to rachis, 160-200 mm apart on rachis, pinnules dichotomously branched, segments 15-22 mm wide; section flat; margins flat; apex softly acuminate, not spinescent; midrib raised above, flat below. Cataphylls narrowly triangular, soft, pilose, 40-60 mm long, articulated. Microsporangiate cones fusiform, cream, 25-40 cm long, 6-8 cm diam. Microsporophyll lamina soft, not dorsiventrally thickened, apex level or raised, apical spine absent. Megasporophylls 11-13 cm long, brown-tomentose; ovules 2-6, glabrous; lamina ovate, 60-70 mm long, 50-60 mm wide, deeply pectinate, with 20-22 soft lateral spines 30-40 mm long, 1.5-2 mm wide, apical spine distinct or not distinct from lateral spines, 30-40 mm long, 3-4 mm wide at base. Seeds flattened-ovoid, 25 mm long, 21 mm wide; sarcotesta yellow, not pruinose, 2 mm thick; fibrous layer absent; sclerotesta verrucose; spongy layer absent.

Historical notes. Though known for several decades, this remarkable species was only recognized as distinct in 1993 by the Chinese botanist C. J. Chen.

Distinguishing features: The bipinnate leaves immediately distinguish this species and the closely related Cycas debaoensis within the genus. Cycas multipinnata is distinguished from the latter by its longer leaves with broader, thinner pinnae that are broadest above the midpoint and its smaller megasporophylls with shorter teeth on the apical lamina. Its subterranean habit, small, soft microsporangiate cones, loose, freely peeling sarcotesta lacking a fibrous layer, and verrucose sclerotesta are features shared by a wider group of related species (Section Stangerioides).

Distribution and habitat: Known from a limited area in the Red River gorge in eastern Yunnan, with a disjunct occurrence in Yen Bai Province, northern Vietnam (Fig. 8). In both occurrences it is found growing in closed evergreen forest on limestone on very steep slopes. Much of the forest habitat has been cleared or severely degraded. Putative hybrids with C. bifida are discussed above.

Conservation status: This species is already severely depleted in the Chinese population and potentially at risk from horticultural collectors. It is regarded as endangered, although further study of the Vietnamese occurrences is essential. IUCN Red List status DD/ CR?

Selected specimens examined: VIETNAM. Yen Bai: Yen Binh, Phuc Ninh, village no. 4, Chang Re Mountain, Hiep 4113 & Hill, 14 Jan 2000 (HN, NSW).

CHINA. Yunnan: Gejiu County, Manhao, Lindstrom s.n. (NSW, HN); Hekou County, Hong 348, 349, Chert, Hill & Stevenson, 6 Ju1 2000 (YUN, NSW, NY, PE).

14. CYCAS FERRUGINEA F. N. Wei, Guihaia 14: 300. 1994.

TYPE: Cult. in Guilin Botanical Garden, introduced from Longzhou County, Guangxi, China, F. N. Wei 2220, 31 Aug. 1994 (HOLOTYPE: IBK).

Literature: Wang (1996), as Cycas miquelii; Chen and Stevenson (1999).

Illustrations: Wei (1994).

Stems arborescent or acaulescent, to 1.2 m tall, 12-18 cm diam. at narrowest point, 10-25 leaves in crown. Leaves deep green or gray-green, highly glossy or semiglossy, 130-210 cm long, slightly keeled or flat (not keeled) in section (opposing pinnae inserted at 150-180[degrees] on rachis), with 120-200 pinnae, with white or orange or brown tomentum shedding as leaf expands or persistent below; rachis usually terminated by paired pinnae. Petiole 35-80 cm long (25-40% of total leaf), glabrous or pubescent, spinescent for 30-100% of length. Basalpinnae not gradually reducing to spines, 80-190 mm long. Median pinnae simple (often falcate), strongly discolorous, 190-380 mm long, 8-13 mm wide, inserted at 70-90[degrees] to rachis, decurrent for 4-8 mm, narrowed to 2.5-4 mm at base (to 25-40% of maximum width), 10-19 mm apart on rachis; section slightly keeled; margins recurved; apex acute, spinescent; midrib raised above, flat below. Cataphylls narrowly triangular, pungent, pilose, 90-120 mm long, persistent. Microsporangiate cones fusiform, orange, 25-45 cm long, 4-6 cm diam. Microsporophyll lamina soft, not dorsiventrally thickened, 16-20 mm long, 9-13 mm wide, fertile zone 15-18 mm long, sterile apex 3-5 mm long, raised, apical spine rudimentary, sharply upturned, 0-3 mm long, or absent. Megasporophylls 11-19 cm long, brown-tomentose; ovules 2-6, glabrous; lamina orbicular, 70-110 mm long, 50-80 mm wide, deeply pectinate, with 28-42 soft lateral spines 18-40 mm long, 1-3 mm wide, apical spine distinct from lateral spines, 15-50 mm long, 3-8 mm wide at base. Seeds ovoid, 19-24 mm long, 15-21 mm wide; sarcotesta yellow, not pruinose, 1-2 mm thick; fibrous layer absent; sclerotesta verrucose; spongy layer absent.

Historical notes: Described by the Chinese botanist Wei Fan-Nan in 1994, from a single plant in cultivation in Guilin. The wild source was not known at the time, and no wild plants have been discovered subsequently in China, making the origin something of a mystery. Field studies in Vietnam in 1997 discovered large populations of a cycad that appears to match the type plant in Lang Son Province, leaving this species most probably a Vietnamese endemic.

Distinguishing features: Closely allied to Cyeas sexseminifera, but immediately distinguished by its dense, dark, ferruginous tomentum on new growth, its longer leaves, and its longer, often falcate, pinnae with recurved margins. It also differs in its generally larger proportions in all respects and its larger and broader megasporophyll lamina with a distinct, broad apical spine.

Distribution and habitat: A restricted species, known from a belt of limestone bluffs in Lang Son and Thai Nguyen Provinces (Fig. 9). This species shows the same habitat preference as Cycas sexseminifera and C. tropophylla, growing on bare limestone faces on steep limestone bluffs, with no visible soil at the roots.

Plants observed in cultivation around Vo Nhai and Yen Son Districts, Thai Nguyen Province, were intermediate in form between Cycas dolichophylla and C. ferruginea and are interpreted as hybrid individuals. In this region C. ferruginea is abundant on steep, exposed limestone faces, and C. dolichophylla is abundant in adjacent closed forests on deep, heavy soils (specimens cited above under C. dolichophylla).

Conservation status: Not considered to be at risk. IUCN Red List status LRnt.

Selected specimens examined: VIETNAM. Lang Son: Huu Lien Nature Reserve, near border post, Huu Lung District (21[degrees]36'30" N, 106[degrees]20'40" E), l0 May 1998, Hill 4995, 4996, 4997, 4998 & Loc (NSW, HN, K, NY, PE, BKF, L, P, MO, CANB); Huu Lien Nature Reserve, near village, Huu Lung District (21[degrees]37'40" N, 106[degrees]22'00" E), 11 May 1998, Hill 5000, 5001, 5002 & Loc (NSW, HN, K, NY, PE, BKF, L, P, MO, CANB); Huu Lung, Huu Lien, Apr 1998, Hiep 2410, 2411, 2412 (HN). Thai Nguyen: Dong Hy, Quang Son, cult. in garden, coll. from steep limestone cliffs 300-400 m to W (21[degrees]41 '50" N, 105[degrees]53'12" E), 16 Mar 1999, Hill 5043 5044 & Loc (HN, NSW); Vo Nhai, La Hien, 20 km NE of Thai Nguyen city, 28 Mar 1996, Yang & Hiep 766 (HN).

CHINA. Guangxi: cult., Guilin Institute of Botany (type plant), 28 Nov 1998, Chen, Zhong & Hill 43 (NSW, PE).

15. CYCAS SEXSEMINIFERA F. N. Wei, Guihaia 16: 1. 1996.

TYPE: Cult. in Guilin Botanical Garden, introduced from Longzhou County, Guangxi, China, F. N. Wei 2223, 1994 (HOLOTYPE: IBK).

Cycas acuminatissima H. T. Chang, Y. C. Zhong & Z. F. Lu, Acta Sci. Nat. Univ. Sunyatseni 37:6 (1998). TYPE: China: Guangxi: Tianyang, Y. C. Zhong 8770, 26 Mar 1998 (HOLOTYPE: SYS n.v.).

Cycas brevipinnata H. T. Chang, Y. Y. Huang & Y. C. Zhong, Acta Sci. Nat. Univ. Sunyatseni 37:8 (1998). TYPE: China: Guangxi: cult. in Nanning Arboretum, H. X. Zheng & Y. Y. Huang 98003, 21 Apr 1998 (HOLOTYPE: SYS n. v.).

Cycas longisporophylla F. N. Wei, Guihaia 17:209 (1997). TYPE: Cult.in Guilin Botanical Garden, introduced from Longzhou County, Guangxi, China, E N. Wei 2222, 19 Jun 1995 (HOLOTYPE: IBK).

Cycas septemsperma H. T. Chang, Y. Y. Huang & H. X. Zheng, Acta Sci. Nat. Univ. Sunyatseni 37:8 (1998). TYPE: China, Guangxi, cult. in Nanning Arboretum, Y. Y. Huang & H. X. Zheng 192, Aug 1998 (HOLOTYPE: SYS n. v.).

Cycas spiniformis J. Y. Liang, in F. N. Wei, Guihaia 17:211 (1997). TYPE: Cult. in Guilin Botanical Garden, introduced from Longzhou County, Guangxi, F. N. Wei 2266, 16 Sep 1995 (HOLOTYPE: IBK).

Cycas miquelii non Warb., sensu Wang (1996), de Laubenfels and Adema (1998), Chen and Stevenson (1999), see below.

Literature: Wang (1996), as Cycas miquelii; Chen and Stevenson (1999), as Cycas miquelii.

Illustrations: Wang (1996), as Cycas miquelii.

Plant arborescent or acaulescent; stems to 0-1 m tall, 8-20 cm diam., 4-20 leaves in crown. Leaves deep green, semiglossy, 50-120 cm long, with brown tomentum shedding as leaf expands, slightly keeled to flat (not keeled) in section (opposing pinnae inserted at 150-180[degrees] on rachis), rachis consistently terminated by paired pinnae, with 80-200 pinnae. Petiole 10-40 cm long (20-35% of total leaf), glabrous, unarmed or spinescent for 5-100% of length. Basal pinnae not gradually reducing to spines, 10-80 mm long. Median pinnae simple, strongly discolorous, 130-240 mm long, 6-10 mm wide, inserted at 70-85[degrees] to rachis, decurrent for 2-6 ram, narrowed to 2-5.5 mm at base (to 25-55% of maximum width), 8-14 mm apart on rachis, section slightly keeled, margins flat or slightly recurved; apex aristate, spinescent; midrib raised above, raised below. Cataphylls narrowly triangular, soft, pilose, 30-50 mm long, persistent. Microsporangiate cones narrowly ovoid to fusiform, yellow, 15-30 cm long, 5-8 cm diam. Microsporophyll lamina soft, not dorsiventrally thickened, 20-30 mm long, 12-30 mm wide, fertile zone 10-28 mm long, sterile apex 2-4 mm long, raised, apical spine rudimentary or absent, sharply upturned, 0-3 mm long. Megasporophylls 8-12 cm long, brown-tomentose; ovules 2-6, glabrous; lamina orbicular, 35-55 mm long, 30-50 mm wide, deeply pectinate, with 16-28 soft lateral spines 10-25 mm long; apical spine distinct from lateral spines, 30-40 mm long. Seeds ovoid, 20-28 mm long, 18-25 mm wide; sarcotesta yellow, not pruinose; fibrous layer absent; sclerotesta smooth to verrucose; spongy layer absent.

Historical notes: Metcalf (1942) applied the name Cycas inermis to this species. Later treatments from China (Cheng et al., 1975; Zhou et al., 1990) also confused it with C. pectinata (which does occur in China, but considerably to the west of this species). Occurrences in Vietnam were overlooked by Leandri (1931), Ho and Duong (1960), Ho (1991), and Hiep and Vidal (1996). Wang (1996) and Chen and Stevenson (1999) applied the name C. miquelii to this species. The treatment under the name C. miquelii by de Laubenfels and Adema (1998) presents a confused concept that includes C. sexseminifera and other taxa. Their neotypification of the name C. miquelii is based on a specimen of a quite different species from southern Thailand (C. clivicola, see below), which is in conflict with the protolog (see excluded names below).

Distinguishing features: This species is most readily distinguished by its dwarf habit with a short stem and short, flat leaves with short, narrow, flat, rather stiff and pungent pinnae and its small but broad megasporophyll lamina with a broad apical spine distinct from the lateral spines. Petioles are often unarmed (hence the misapplication of the epithet "inermis"), but this character is not at all consistent.

Distribution and habitat: Widespread in southern and central Guangxi Province of China and in Cao Bang Province in central northern Vietnam in the border region with Guangxi, with a disjunct occurrence in Thanh Hoa Province south of Hanoi (Fig. 9). Locally abundant, growing in crevices in bare outcrops in rugged karst limestone country, often on vertical faces with no visible soil.

Conservation status: Although there is a clear demand for this species in horticultural markets in China and Vietnam, and a substantial collection from the wild for this trade, this species is extremely abundant in many inaccessible sites and is not considered to be at risk. IUCN Red List status LRnt.

Selected specimens examined: VIETNAM. Cao Bang: Thach An, Thuy Hung (22[degrees]24'58" N, 106[degrees]27'33" E), 1 Dec 1996, Averyanov et al. CBL912 (HN), 4 Dec 1996, Averyanov et al. CBL878 (HN); Quang Hoa, Quoc Phong, Lung Trang (22[degrees]41 '40" N, 106[degrees]27'09" E), alt. ca. 400 m, 14 Mar 1999, Hill 5031 & Loc (HN, NSW). Ninh Binh: Nho Quan, Cuc Phuong, Nga village (20[degrees]14' 15" N, 105[degrees]43'10" E), outside entrance to Cuc Phuong National Park, cult. in garden, coll. on hill behind village, 19 Mar 1999, Hill 5053 & Loc (HN, NSW); Bich Dong, 25 Oct 1994, Yang & Hiep SLY526 (HN). Thanh Hoa: Nhu Xuan, Ben En National Park, 21 Oct 1996, Hiep 2114 (HN), 30 Mar 1996, Loc P7063 (FIN).

CHINA. Guangxi: Longzhou County, Long Gan natural reserve (22[degrees]31'24" N, 106[degrees]50'36" E), alt. 240 m, 2l Nov 1998, Chen, Zhong & Hill 31, 32 (NSW, PE) (22[degrees]33'35" N, 106[degrees]47'47" E), Chen, Zhong & Hill 33 (NSW, PE); cult. in nursery of Nanning Forestry Research Center, Nanning, coll. from southern Guangxi (same collection as type plant of C. brevipinnata, separate plant), 7 Nov 1998, Chen, Zhong & Hill 2 (NSW, P, PE); cult. in Qing Xui Wu park, Nanning, coll. from southern Guangxi, 7 Nov 1998, Chen, Zhong & Hill 5 (NSW, PE); cult. in Longzhou city park, coll. nearby, 21 Nov 1998, Chen, Zhong & Hill 34, 35 (NSW, PE).

16. CYCAS TROPOPHYLLA K. D. Hill & Phan K. Loc, sp. nov. (Fig. 10).

[FIGURE 10 OMITTED]

TYPE: Vietnam: Quang Ninh: island in Ha Long Bay (21[degrees]50'47" N, 107[degrees]02'29" E), K. D. Hill 5020, Phan K. Loc & N. V. Dzu, 10 Mar 1999 (HOLOTYPE: HN; ISOTYPE: NSW, K, NY).

A Cycade sexseminifera statura maiore, foliis carinatis, foliolis confertis, megasporophyllis maioribus, a Cycade ferruginea foliis carinatis, foliolis confertis brevioribus planis differt.

Plant arborescent or acaulescent; stems to 0-1 m tall, 12-20 cm diam., 10-40 leaves in crown. Leaves deep green, semiglossy, 130-210 cm long, with brown tomentum shedding as leaf expands, slightly keeled to flat (not keeled) in section (opposing pinnae inserted at 150-180[degrees] on rachis), rachis consistently terminated by paired pinnae, with 120-200 pinnae. Petiole 35-80 cm long (25-35% of total leaf), glabrous, spinescent for 30-100% of length. Basal pinnae not gradually reducing to spines, 80-190 mm long. Median pinnae simple, strongly discolorous, 190-270 mm long, 8-13 mm wide, inserted at 70-90[degrees] to rachis, decurrent for 2-5 mm, narrowed to 2.5-4 mm at base (to 20-30% of maximum width), 10-16 mm apart on rachis, section slightly keeled, margins slightly recurved; apex aristate, spinescent; midrib raised above, raised below. Cataphylls narrowly triangular, soft, pilose, 100-120 mm long, persistent. Microsporangiate cones narrowly ovoid to fusiform, yellow, 25-45 cm long, 4-6 cm diam. Microsporophyll lamina soft, not dorsiventrally thickened, 16-20 mm long, 9-13 mm wide, fertile zone 15-18 mm long, sterile apex 3-5 mm long, raised, apical spine rudimentary or absent, sharply upturned, 0-2 mm long. Megasporophylls 11-16 cm long, brown-tomentose; ovules 2-6, glabrous; lamina orbicular, 70-120 mm long, 55-80 mm wide, deeply pectinate, with 24-42 soft lateral spines 18-35 mm long, 1-2 mm wide, apical spine distinct from lateral spines, 15-21 mm long, 4-8 mm wide. Seeds ovoid, 20-28 mm long, 18-25 mm wide; sarcotesta yellow, not pruinose; fibrous layer absent; sclerotesta smooth to verrucose; spongy layer absent.

Historical notes. This distinctive taxon was totally overlooked in the past.

Distinguishing features: Closely allied to Cycas sexseminifera but immediately distinguished by its keeled leaves. It also differs in its generally larger proportions in all respects and in its larger and broader megasporophyll lamina with a distinct, broad apical spine. It is distinguished from C. ferruginea by its keeled leaves and short, flat pinnae.

Distribution and habitat. A restricted species, known from Cat Ba and other islands in Haiphong Harbor and on similar limestone bluffs on the adjacent mainland, Haiphong and Quang Ninh Provinces (Fig. 9). This species shows the same habitat preference as Cycas sex-seminifera and C. ferruginea, growing on bare limestone faces on steep limestone bluffs, with no soil accumulation at the roots.

Conservation status: An abundant species in inaccessible habitats. Not considered to be at risk. IUCN Red List status LRnt.

Etymology: From the Greek tropis, the keel of a ship, and phyllon, leaf, in reference to the keeled leaves that distinguish this species from closely related species.

Selected specimens examined: VIETNAM. Quang Ninh: island in Ha Long Bay (20[degrees]50'47" N, 107[degrees]02'29" E), Hill 5021, Loc & Dzu, 10 Mar 1999 (HN, NSW); Thong Nhat, Da Trang (21[degrees]03'14" N, 107[degrees]03'45" E), 11 Mar 1999, Hill 5024, Loc & Dzu (HN, NSW); Cam Pha, 26 Mar 1996, Yang & Hiep SLY759 (HN). Haiphong: Cat Ba National Park (20[degrees]47' N, 106[degrees]50' E), 20 Oct 1994, Yang & Hiep SLY502, SLY504 (HN); Cat Ba National Park (20[degrees]47, N, 107[degrees]0' E), 20 Oct 1994, Yang & Hiep SLY510, SLY12, NTH2002 (HN).

B. Section INDOSINENSES Schuster

Cycas section lndosinenses Schuster, Pflanzenr. 99: 65. 1932. TYPE: Cycas siamensis Miq., lecto, fide Hill and Yang (1999). This is one of only two species included in this section by Schuster and the single species remaining when the other species (C. micholitzii) is removed to section Stangerioides, as was done by Smitinand (1971).

Section Indosinenses is defined by its combination of glabrous ovules and deeply pectinate megasporophyll lamina and by the presence of a layer of fibrous tissue within its sarcotesta. It is a taxonomically complex group requiring extensive study, ranging from Himalayan India east to Vietnam and southern China and southward to northern peninsular Malaysia. Sectional circumscription herein follows Wang (1996). Seven species occur in Vietnam, mostly in the south (Figs. 1, 11).

[FIGURE 11 OMITTED]

17. CYCAS PECTINATA Buch.-Ham.

Cycaspectinata BucK-Ham., Mem. Were. Nat. Hist. Soc. 5(2): 322-323. 1826. Cycas circinalis subsp, vera var. pectinata (Griff.) Schuster, Pflanzenr. 99:68 (1932). TYPE: India, E. Bengal, Chittagong, J. D. Hooker & Thompson 6, 1855 (NEOTYPE, here designated: K; NEOISOTYPE: P). This specimen was designated the lectotype by de Laubenfels and Adema (1998), but this cannot be maintained since the specimen was collected after the species was published. The same specimen is here designated the neotype.

Cycas pectinata Griff., Not. P1. Asiat. 4:10.1854; Ic. P1. Asiat. 4: pl. 360, fig. 3. 1854; nom. illegit., later homonym of C. pectinata Buch.-Ham. (Mem. Wern. Nat. Hist. Soc. 5(2): 322. 1826). TYPE: Icones Plantarum Asiatarum 4: pl. 360, fig. 3. 1854.

Cycas jenkinsiana Griff., Not. pl. Asiat. 4: 9-10, pl. 360, figs. 1-2 and pl. 362, fig. 1. 1854. TYPE: India, Assam, Jenkins s.n. (HOLOTYPE: K; ISOTYPE: BM, L).

Literature: Chen and Stevenson (1999).

Illustrations: Smitinand (1971); Cheng et al. (1975); Grierson and Long (1983); Wang (1996); Tang et al. (1997); Hill and Yang (1999).

Plant arborescent; stems to 1-12 m tall, 14-20 cm diam., 30-40 leaves in crown. Leaves deep green to gray-green, semiglossy, 150-240 cm long, with white tomentum shedding as leaf expands, flat (not keeled) in section (opposing pinnae inserted at 170 180[degrees] on rachis), with 180-312 pinnae, rachis consistently terminated by a spine 1-46 mm long. Petiole 30-80 cm long (25-50% of total leaf), glabrous, spinescent for 30-80% of length. Basal pinnae not gradually reducing to spines, 50-160 mm long. Median pinnae simple, strongly discolorous, 200-315 mm long, 7.5-10.5 mm wide, inserted at 45-60[degrees] to rachis, decurrent for 4-8 mm, narrowed to 2.5-4 mm at base (to 35-45% of maximum width), 8-13 mm apart on rachis, section flat, margins slightly recurved; apex acute, spinescent to not spinescent; midrib raised above, raised below. Cataphylls narrowly triangular, soft, pilose, articulated. Microsporangiate cones ovoid, yellow or green, 30-55 cm long, 16-22 cm diam. Microsporophyll lamina firm, not dorsiventrally thickened, 43-60 mm long, 19-24 mm wide, fertile zone 35-57 mm long, sterile apex 3-8 mm long, level, apical spine prominent, sharply upturned, 17-32 mm long. Megasporophylls 22-30 cm long, gray-tomentose; ovules 2-4, glabrous; lamina orbicular, 110180 mm long, 100-130 mm wide, deeply pectinate, with 40-50 soft lateral spines 26-75 mm long, 2-3 mm wide; apical spine distinct from lateral spines, 35-75 mm long, 5-12 mm wide at base. Seeds flattened-ovoid, 42-45 mm long, 33-45 mm wide; sarcotesta yellow, not pruinose, 4-7 mm thick; fibrous layer present; sclerotesta smooth; spongy layer absent.

Historical notes: Cycas pectinata was the fourth species of Cycas to be named, described in 1826 by the Scottish surgeon and botanist Francis Buchanan-Hamilton. No type was cited, but reference was made to occurrence in "the hills which bound Bengal to the east," and the description cited "Habitat in Camrupae orientalis sylvis." Cycas angulata R. Brown and Olus calappoides of Rumphius (C. rumphii) were cited (erroneously) in synonymy. Zhou et al. (1990) regarded Hamilton's publication as illegitimate because C. angulata was cited as a synonym. The latter was cited, but with a question mark, indicating that the author was unsure of the placement of C. angulata. This does not invalidate Hamilton's publication (see Greuter, 1994, Art. 63.1, note 1, example 6). The primary set of Hamilton's Bengal collections eventually went to Wallich and thence to Kew (K-W). A second set went to E. Neither set includes a specimen that could be regarded as the type of C. pectinata.

The name has been attributed to Griffith, although he did not actually add his name to the binomial when describing it (Griffith's practice apparently was to add his name to new binomials and place no name on existing or previously published binomials).

Distinguishing features: The very large, ovoid microsporangiate cones with long, narrow microsporophylls, those with long apical spines, readily distinguish this species from others in the Cycas pectinata group. The thin, smooth bark also distinguishes this species from related taxa, although this feature is shared with C. clivicola and C. elongata.

Distribution and habitat: Common and widespread in forest on hills of the central highlands, mostly above about 500 m altitude (Fig. 11). This species occurs in medium to tall forest on deep, often clay-rich, and more fertile soils, usually as part of the general shrub understory at medium to higher elevations in generally moist conditions in moderate to deep shade. Although often found on limestone substrates, it is by no means restricted to these, and it also occurs on granites and metasediments.

Cycas pectinata is abundant in the hill forests in parts of northeastern India and has also been collected from Nepal and Bhutan. It extends into Yunnan Province in southern China, and eastward into Thailand, Laos, and Vietnam.

Conservation status." A very widespread species. Although its habitat is continually being reduced, large populations remain, and it is not under any immediate threat of extinction. IUCN Red List status VU A2c (on the basis of the continuing population decline, although the very large populations remaining indicate that the short-term threat of extinction is low).

Selected specimens examined: VIETNAM. Gia Lai: Yu An, Tu Thuy, between An Khe and Kbang (14[degrees]01' N, 108[degrees]41' E), 30 Oct 1994, Yang 531, Ban & Lindstrom (HN); Kbang (14[degrees]04' N, 108[degrees]40' E), 30 Oct 1994, Yang 532, Ban & Lindstrom (HN). Kon Tum: between Dak Poko and Dak Mek Rivers, alt. 1000 m, 28 Mar 1995, US Nat. Geog. Soc. Exped. VH 962. 963 (HN); Dak Poko River near Dak Gley township, alt. 600 m, 29 Mar 1995, US Nat. Geog. Soc. Exped. VH 1017, 1018 (HN); along Dak Poko River 6 km N of Dak Gley township, alt. 600-700 m, 16 Apr 1995, US Nat. Geog. Soc. Exped. VH 13851387 (HN), 28 Nov 1995, VH 2078 (FIN), 29 Nov 1995, VH 214-6 (HN). Lam Dong: Dalat, 5 Nov 1994, Yang 542, 543, Ban & Lindstrom (HN). Quang Ngai: Duc Pho, Pho Khanh, 25 Jan 2000, Hiep 4162, 4163, 4164 & Hill (HN, NSW).

BANGLADESH. Chittagong, Hooker & Thompson Herb. Ind. Or (BM, K, L); Satakoina, Chittagong, Hooker & Thompson 595 , 11 Jan 1857 (K).

BHUTAN. E bank of Dangme Chu, between Cha Zam and Duksun, N of Tashigang, Grierson & Long 2357, 29 Jun 1979 (K ex E).

MYANMAR. Shan states, Aplin s.n., Nov-Dec 1887 (K); Mundat, Kingdon Ward 22308, 18 May 1956 (K); Rangoon, Meebold 8166, Jan 1908 (K).

CHINA. Yunnan, Henry 13637 (K, NY); Meng Yuan District, Meng La Natural Reserve, Lindstrom s.n., 1994 (NSW).

INDIA. Gowatty, Clark 43243, 29 Mar 1886 (K); Satte Bhaia Jhai, Darij Serai, Gamble 2675A, Jan 1875 (K); Rammagar Hills, Haines 3983, Nov 1916 (K); Great Rungeet Valley, Sikkim, Hooker s.n., 1848 (K); Khasia, Hooker & Thompson, 16 Jul 1850 (K); Laki, Lakhei County, Lushai Hills, Assam, Parry 100, Feb 1927 (K); Koongi Valley, Manipur, Watt 6796, 27 Apr 1882 (K).

NEPAL. Mechizou Jhapa District, Nicolson 3078, 31 Mar 1967 (BM); Ganjbari (26[degrees]45' N, 87[degrees]58' E), Stainton 5733, 1 Apr 1967 (BM); Udaipur Ganhi (26[degrees]56' N, 86[degrees]31' E), Stainton 6638, 3 Nov 1969 (BM).

THAILAND. Chaiyaphum: near Chulaphom Dam, Larsen, Supee, Larsen, Nielsen & Santisuk 31432, 5 Aug 1972 (BKF). Chiang Mai: Doi Pha Hom Pok, Fang, Kerr 5218, 3 Apr 1921 (BM, K). Kanchanaburi: Ban Huay Sue, E of Thong Pha Phum, Hill 4645, 02 May 1994 (NSW, BKF, K, L, PE). Loei: Phu Paek, van Beusekom & Phengklai 3027, 14 Jan 1970 (L ex BKF). Mae Hong Son: Ban Mok Jum Prak, Hill 4638, 26 Apr 1994 (NSW). Phetchabun: N of Chai Badun, Abbe, Abbe & Smitinand 9361 B, 2 Jan 1960 (BKF). Phrae: Mae Kating, Williams & Smitinand 17133 (BKF). Sukhothai: Khao Luang, Kerr 5944, 4 May 1922 (BM, K).

18. CYCAS CLIVICOLA K. D. Hill

Cycas clivicola K. D. Hill, Brittonia 51 : 62, fig. 8. 1999. TYPE: Thailand: Pak Meng Beach, W of Trang, K. D. Hill 4633 & Poonsak Vatcharakorn, 22 Apr 1994 (HOLOTYPE: NSW; ISOTYPE: BKF, K, L, PE).

One subspecies has been recorded from Vietnam.

CYCAS CLIVICOLA subsp. LUTEA K. D. Hill

Cycas clivicola subsp, lutea K. D. Hill, Brittonia 51: 64, figs. 8e, f, i. 1999. TYPE: Thailand: NW of Ban Nam Sai, K. D. Hill 4620 & Poonsak Vatcharakorn, 17 Apr 1994 (HOLOTYPE: NSW; ISOTYPE: BKF, K, L, PE).

Cycas elongata in part, sensu de Laubenfels and Adema (1998).

Illustrations: Tang et al. (1997); Hill and Yang (1999).

Plant arborescent; stems to 6 m tall, 12-16 cm diam., 45-100 leaves in crown. Leaves bright green or gray-green (when young), semiglossy, 90-160 cm long, with white tomentum shedding as leaf expands, slightly keeled to flat (not keeled) in section (opposing pinnae inserted at 150-180[degrees] on rachis), with 130-200 pinnae, rachis usually terminated by a spine 2-30 mm long. Petiole 20-45 cm long (20-30% of total leaf), glabrous, spinescent for 0-70% of length. Basalpinnae not gradually reducing to spines, 50-200 mm long. Median pinnae simple, weakly discolorous, 100-260 mm long, 5-11 mm wide, inserted at 60-80[degrees] to rachis, decurrent for 3-8 mm, narrowed to 1.5-3.5 mm at base (to 25-35% of maximum width), 8-14 mm apart on rachis, section flat, margins flat; apex acute, spinescent; midrib raised above, raised below. Cataphylls narrowly triangular, soft, pilose, 60-80 mm long, articulated. Microsporangiate cones narrowly ovoid, yellow to brown, 20-25 cm long, 8-9 cm diam. Microsporophyll lamina firm, not dorsiventrally thickened, 30-35 mm long, 18-19 mm wide, fertile zone 25-30 mm long, sterile apex 5-6 mm long, level, apical spine prominent, sharply upturned, 5-5 mm long. Megasporophylls 12-18 cm long, yellow-tomentose to gray-tomentose; ovules 2-4, glabrous; lamina orbicular, 90-120 mm long, 45-70 mm wide, deeply pectinate, with 24-40 soft lateral spines 25-30 mm long, 1.5-2 mm wide; apical spine distinct from lateral spines, 45-75 mm long, 3-5 mm wide at base. Seeds flattened-ovoid, 38 mm long, 28 mm wide; sarcotesta orange, not pruinose, 3 mm thick; fibrous layer present; sclerotesta smooth; spongy layer absent.

Distinguishing features: The smooth trunks and relatively small microsporangiate cones with small, short microsporophylls and thickened axes distinguish this species within Vietnam. Subsp. lutea differs from subsp, clivicola in the larger microsporangiate cones with longer and broader sporophylls, but these are still small in comparison to related taxa in Vietnam.

Distribution and habitat: The main distribution of this species is peninsular Thailand and Malaysia for subsp, clivicola, with subsp, lutea in southeastern Thailand and Cambodia, just extending to Vietnam in Kien Giang and Minh Hai Provinces (Fig. 11). A common species on limestone outcrops in this region, plants are most often rooted in clefts and crevices in nearvertical cliffs, in full sun and often with no soil at the roots.

Conservation status: Abundant and widespread in generally inaccessible sites. Not regarded as threatened. IUCN Red List status LRnt.

Selected specimens examined: VIETNAM. An Giang; Bay Nui Mt, leg. ign. (Botany Dept., Univ. Ho Chi Minh). Kien Giang: near Ha Tien, Yang 561 per Long, 17 Nov 1994 (FTG); Nui Com, Kien Luong, leg. ign. (Botany Dept., Univ. Ho Chi Minh).

CAMBODIA. Kampong Spoe, Pierre 532 p.p., Apr 1870 (P); between Batdambang and Sisophon, Schmid s.n., Dec 1954 (P).

THAILAND. Prachinburi: SW of Aranyapathet, Yang s.n. (FTG). Rayong: NW of Ban Nam Sai, Hill 4620A, B, 17 Apr 1994 (NSW, BKF, K, L, PE); near Ba Nam Sai, Yang 620, Tang & Vatcharakorn, 23 Jan 1995 (FTG).

19. CYCAS ELONGATA (Leandri) D. Yue Wang

Cycas elongata (Leandri) D. Y. Wang, Cycads China: 51. 1996, as Cycas elonga. Cycas pectinata var. elongata Leandri, Fl. Gen. Indo-Chine 5(10): 1091. 1931. Epicycas elongata (Leandri) S. L. Yang, in de Laub. & Adema, Blumea 43: 393. 1998. TYPE: Vietnam: Ninh Thuan (Phan Rang), Ca Na, Poilane 9328 (LECTOTYPE, here designated: P). This is the specimen that best matches the original description of the megasporophyll of the two Poilane collections held in P.

Cycas inermis non Lour., sensu Ho (1991).

Illustrations: Ho (1991), as Cycas inermis; Wang (1996), as Cycas elonga.

Stems arborescent, to 2-5 m tall, 10-20 cm diam. at narrowest point, 30-60 leaves in crown. Leaves bright green or gray-green, semiglossy, 90-140 cm long, moderately keeled (opposing pinnae inserted at 90-150[degrees] on rachis), with 130-240 pinnae, with white tomentum shedding as leaf expands; terminated by a spine or paired pinnae. Petiole 20-40 cm long (20-30% of total leaf), glabrous, spinescent for 60-100% of length. Basalpinnae not gradually reducing to spines, 45-60 mm long. Median pinnae simple, strongly discolorous, 140-190 mm long, 8-11 mm wide, inserted at 50-60[degrees] to rachis, decurrent for 3-5 mm, narrowed to 2.5-4.5 mm at base (to 30-40% of maximum width), 10-18 mm apart on rachis; section flat; margins flat; apex acute, not spinescent; midrib raised above, raised below. Cataphylls narrowly triangular, soft, thinly sericeous or lacking tomentum, 60-90 mm long. Microsporangiate cones narrowly ovoid, orange or brown, 25-35 cm long, 9-13 cm diam. Microsporophyll lamina firm, not dorsiventrally thickened. Megasporophylls 20-27 cm long, gray-tomentose or brown-tomentose; ovules 2-6, glabrous; lamina ovate, 130-180 mm long, 50-70 mm wide, deeply to moderately pectinate, with 36-38 soft lateral spines 20-25 mm long, 1-2 mm wide, apical spine distinct from lateral spines, 30-55 mm long, 4-5 mm wide at base. Seeds flattened-ovoid, 40 mm long, 30 mm wide; sarcotesta yellow; fibrous layer present; sclerotesta smooth; spongy layer absent (Fig. 12).

[FIGURE 12 OMITTED]

Historical notes: Described in 1931 as variety of Cycas pectinata by the French botanist Leandri. The circumscription of Epicycas elongata as published by de Laubenfels and Adema (1998) includes C. clivicola (see above).

Distinguishing features: Nearest to Cycas pectinata, from which it can be distinguished by its keeled leaves with broader adult and seedling pinnae and by its narrower megasporophyll apex with shorter lateral spines. Microsporangiate cones are smaller, with shorter microsporophylls, themselves with shorter apical spines.

Distribution and habitat: Coastal hills in southern Vietnam, from Nha Trang northward to Quang Ngai, Khanh Hoa, Phu Yen, and Binh Dinh Provinces (Fig. 11). Locally abundant in forests to open shrublands on slopes, on gritty soil derived from coarse siliceous granite.

Conservation status: Although habitat is being reduced and a significant trade occurs in this species, it is not considered to be at risk in the short term. IUCN Red List status VU A2c.

Selected specimens examined: VIETNAM. Khanh Hoa: Nha Trang, Averyanov & Kudryavtzeva 248 (LE); cult. in Cam Ranh, coll. from low granite hills a few km to W (ca. 12[degrees]00' N, 109[degrees]05' E), 18 May 1998, K. D. Hill 5007 (NSW, HN, K, NY, PE, L); low granite hills near Dong Lac, west of Cam Ranh Bay (11[degrees]58'22" N, 109[degrees]03'42" E), 20 May 1998, K. D. Hill 5009 (NSW, HN, K, NY, PE, L), 10 km N of Nha Trang beside highway, 5 Nov 1994, Yang 540, Ban & Lindstrom (HN). Ninh Thuan: near Tram de Hoa Cat, 14 km N of Nha Trang, Poilane 4656 (P); Ca Na, Poilane 9095 (P); Phan Rang, 5 Nov 1994, Yang 547, Ban & Lindstrom (HN). Phu Yen: Song Cau, Xuan Loc, Cu Mong pass, 26 Jan 2000, Hiep 4180, 4184, 4184 & Hill (HN, NSW).

20. CYCAS PACHYPODA K. D. Hill, sp. nov. (Fig. 13).

[FIGURE 13 OMITTED]

TYPE: Vietnam: Binh Thuan: Tuy Phong, Vinh Hao (11[degrees]20'22" N, 108[degrees]51'17" E), 20 May 1998, Hill 5012 (HOLOTYPE: HN; ISOTYPE: NSW, K, NY, PE, BKF, L, P, MO).

Cycadem siamensem foliis non carinatis, cortice crasso suberoso, trunco basi crasso simulans, sed a Cycade siamensi statura foliis foliolisque maioribus, foliolis carinatis, strobilis masculis maioribus microsporophyllis longioribus et apice longiore differt.

Plant arborescent, stems to 0.5-1.5 m tall, 12-17 cm diam. at narrowest point, 50-80 leaves in crown. Leaves deep green or gray-green, semiglossy, 90 130 cm long, slightly keeled or flat (not keeled) in section (opposing pinnae inserted at 150-170[degrees] on rachis), with 160-250 pinnae, with white tomentum shedding as leaf expands; rachis usually terminated by a spine 5-15 mm long. Petiole 10-20 cm long (10-20% of total leaf), glabrous, spinescent for 80-100% of length. Basalpinnae short but not gradually reducing to spines, 15-45 mm long. Median pinnae simple, strongly discolorous, 120-180 mm long, 6-7 mm wide, inserted at 50-60[degrees] to rachis, decurrent for 3-5 mm, narrowed to 2.5-3.5 mm at base (to 40-50% of maximum width), 6-12 mm apart on rachis; section flat or slightly keeled; margins flat or slightly recurved; apex acute, spinescent; midrib raised above, raised below. Cataphylls narrowly triangular, soft, thinly sericeous or lacking tomentum, 80-110 mm long. Microsporangiate cones narrowly ovoid, orange or brown, 25-40 cm long, 10-15 cm diam. Microsporophyll lamina firm, not dorsiventrally thickened, 40-52 mm long, 17-20 mm wide, fertile zone 30-40 mm long, sterile apex 7-12 mm long, level, apical spine prominent, sharply upturned, 9-15 mm long. Megasporophylls 7-15 cm long, brown-tomentose; ovules 2-4, glabrous; lamina orbicular, 90-120 mm long, 40-70 mm wide, deeply pectinate, with 30-36 soft to pungent lateral spines 10-20 mm long, 1-2 mm wide, apical spine distinct from lateral spines, 15-40 mm long, 4-5 mm wide at base. Seeds flattened-ovoid; sarcotesta yellow; fibrous layer present; sclerotesta smooth, spongy layer absent.

Distinguishing features: Cycas pachypoda is distinguished by its very broad and abruptly swollen base, its thick, fissured, and corky bark, its slightly keeled or flat leaves with short petioles and stiff, narrow leaflets, its medium microsporangiate cones with shorter apical spines on the microsporophylls, and its overall small megasporophylls. Cycas siamensis is similar in its swollen base and thick bark but can be distinguished by its much smaller microsporangiate cones and its flat leaves with more persistent tomentum and lower pinnae gradually reducing to spines. Its short, mostly spinescent petioles distinguish C. pachypoda from C. clivicola and C. condaoensis. Microsporangiate cones of C. pachypoda are also larger than those of these two species and have longer microsporophylls.

Distribution and habitat. Known only from a limited range of coastal hills in southern Vietnam, Bin Thuan and Dong Nai Provinces (Fig. 11). Locally abundant in dry, open thorn shrublands on rocky slopes, on dry, gritty soil derived from coarse siliceous granite. Original vegetation in much of this region was low monsoon woodland and thorn scrub, although much of the original woodland has been cut for fuel.

Conservation status: Not considered to be at risk in the short term but requiring study of actual population extent. IUCN Red List status DD/?LR.

Etymology: From the Greek pachy-, thick, and podos, foot, referring to the distinctive and very large swollen base of this species.

Selected specimens examined: VIETNAM. Birth Thuan: Tuy Phong, Vinh Hao (11[degrees]20'22" N, 108[degrees]51'17" E), 20 May 1998, Hill 5010, 5011 (NSW, HN, K, NY, PE, BKF, L, P, MO). Ninh Thuan: Ca Na, 4 Nov 1994, Yang 547, 548, 551 (HN).

21. CYCAS CONDAOENSIS K. D. Hill & S. L. Yang, sp. nov. (Fig. 14).

[FIGURE 14 OMITTED]

TYPE: Vietnam: Poulo Condor [Con Dao], L. Pierre 1722, Sep 1877 (HOLOTYPE: K; ISOTYPE: A, L, NY).

Cycadem siamensem foliis non carinatis, cortice crasso suberoso, trunco basi crasso simulans, sed a Cycade siamensi statura foliis foliolisque maioribus, foliolis latioribus, strobila mascula magniore, a Cycade pachypoda foliolis latioribus, petiolis longiore minus spinescens, strobilis masculis minoribus differt. Cycas inermis non Lour., sensu Hiep and Vidal (1996).

Plant arborescent, stems to 0.2-2.5 m tall, 14-17 cm diam., 12-70 leaves in crown. Leaves bright green, semiglossy, 70-175 cm long, with white or brown tomentum shedding as leaf expands, flat (not keeled) in section (opposing pinnae inserted at 180[degrees] on rachis), with 130-260 pinnae, rachis usually terminated by paired pinnae. Petiole 20-50 cm long (15-30% of total leaf), glabrous, spinescent for 0-60% of length. Basalpinnae not gradually reducing to spines, 25-120 mm long. Medianpinnae 130-240 mm long, 7-11.5 mm wide, inserted at 60-75[degrees] to rachis, decurrent for 3-6 mm, narrowed to 2-3 mm at base (to 20-40% of maximum width), 5-17 mm apart on rachis, section flat, margins slightly recurved; apex acute, not spinescent; midrib raised above, raised below. Cataphylls narrowly triangular, pungent, thinly sericeous or lacking tomentum, 5060 mm long, persistent. Microsporangiate cones narrowly ovoid, orange or brown to green, 26-31 cm long, 9-12 cm diam. Microsporophyll lamina firm, not dorsiventrally thickened, 30-50 mm long, 12-20 mm wide, fertile zone 23-36 mm long, sterile apex 7-11 mm long, level, apical spine prominent, sharply upturned, 4-5 mm long. Megasporophylls 9-17 cm long, yellow-tomentose or pale brown-tomentose; ovules 2-4, glabrous; lamina orbicular, 60-120 mm long, 35-55 mm wide, deeply pectinate, with 20-32 soft lateral spines 8-18 mm long, 1.5-2 mm wide, apical spine distinct from lateral spines, 25-60 mm long, 4-10 mm wide at base. Seeds ovoid, 39-43 mm long, 3336 mm wide; sarcotesta orange to yellow, not pruinose, 4-6 mm thick; fibrous layer present; sclerotesta smooth; spongy layer absent.

Distinguishing features: Cycas condaoensis is somewhat intermediate between C. siamensis and the C. pectinata group in many characters. The small oblong microsporangiate cone distinguishes it from the C. pectinata group, while the glabrous leaf with basal pinnae not gradually reducing to spines separates it from C. siamensis. The thick, corky bark on the trunk and the inflated base with similar thick, corky bark are other similarities with C. siamensis, although these features are also shared with C. pachypoda. Microsporangiate cones of C. condaoensis are intermediate in size between those of C. siamensis and C. paehypoda.

Distribution and habitat: Endemic on the Con Dao group of islands (Fig. 11). Several populations are known, mostly in drier sites on sand accumulations, either old beach dunes or wind-blown beach-sand deposits. Habitat ranges from low, open shrubland to dense, tall shrubland or woodland.

Conservation status: Not considered to be at risk in the short term, though of limited range and population size. IUCN Red List status VII D2.

Etymology: From its occurrence as an endemic species on the Con Dao group.

Selected specimens examined: VIETNAM. Ba Ria-Vung Tau: Con Dao islands, Averyanov & Kudryavtzeva 361 (LE); cult. in Kew 1880, plants ex Poulo Condor via van Houtte 250/1877 (K); cult. in Kew 1881, plants ex Poulo Condor via van Houtte 250/1870 (K).

22. CYCAS LINDSTROMII S. L. Yang, K. D. Hill & N. T. Hiep

Cycas lindstromii S. L. Yang, K. D. Hill & N. T. Hiep, Novon 7: 213. 1997. Epicycas lindstromii (S. L. Yang, K. D. Hill & N. T. Hiep) de Laub., in de Laub. & Adema, Blumea 43: 389. 1998. TYPE: Vietnam: Binh Thuan, Tuy Phong, Xa Chi Cong, near Doc Bao Da (11[degrees]13' N, 108[degrees]38' E), alt.25 m, S.-L. Yang 557, 11 Nov 1994 (HOLOTYPE: FTG n.v.; ISOTYPE: NSW, S n.v.).

Illustrations: Yang et al. (1997).

Plant acaulescent, stems to 5-8 cm diam., 6-25 leaves in crown. Leaves bright green (yellowish green beneath), highly glossy, 40-100 cm long, with brown tomentum shedding as leaf expands, moderately keeled (opposing pinnae inserted at 90-130[degrees] on rachis), with 50-140 pinnae, rachis consistently terminated by paired pinnae. Petiole 15-35 cm long (25-40% of total leaf), glabrous, spinescent for 50-100% of length. Basalpinnae not gradually reducing to spines, 35-120 mm long. Median pinnae simple, strongly discolorous, 100-170 mm long, 7-11 mm wide, inserted at 45-60[degrees] to rachis, decurrent for 3-5 mm, narrowed to 2-3 mm at base (to 20-35% of maximum width), 7-13 mm apart on rachis, section flat, margins flat; apex acute, not spinescent; midrib raised above, raised below. Cataphylls linear, soft, pilose, 20-50 mm long, 3-7 mm wide at base, persistent. Microsporangiate cones fusiform, yellow, 12-20 cm long, 4-5 cm diam. Microsporophyll lamina firm, not dorsiventrally thickened, 10-16 mm long, 8-15 mm wide, fertile zone 7-12 mm long, sterile apex 3-4 mm long, level, apical spine rudimentary, sharply upturned, 2-8 mm long. Megasporophylls 8-20 cm long, gray-tomentose; ovules 2-4, glabrous; lamina ovate, 50-100 mm long, 15-40 mm wide, deeply pectinate, with 8-26 soft lateral spines 8-30 mm long, 1.5-3 mm wide; apical spine distinct from lateral spines, 10-50 mm long, 1.5-4 mm wide at base. Seeds ovoid, 29-37 mm long, 20-33 mm wide; sarcotesta orange, not pruinose, 3.5-4 mm thick; fibrous layer present; sclerotesta smooth; spongy layer absent.

Distinguishing features: Cycas lindstromii is distinguished by its subterranean and frequently branched trunk, its short, keeled leaves with basal pinnae not progressively reducing to spines, its small, slender microsporangiate cones, and its relatively narrower and more elongated megasporophyll lamina. Although remarkably different from other members of the C. pectinata group, these differences are mainly autapomorphic, and it is clearly placed in that group by its pectinate megasporophyll apex and fibrous sarcotesta.

Distribution and habitat: This species occurs in grassland and mixed dry, open forest or woodland often dominated by Dipterocarpus tuberculatus on flat sites at low elevations and near the coast along the east coast of southern Vietnam (Fig. 11). Soil is deep and sandy, a combination of outwash from siliceous granite hills and beach dune sands.

Conservation status: Local residents in this area have been extensively collecting wild plants for sale as garden and landscape subjects. This species is consequently regarded as an endangered species, under threat of extinction should this practice continue. IUCN Red List status VU A2e.

Selected specimens examined: VIETNAM. Ba Ria-Vung Tau: Xuyen Moc, 20 Nov 1994, Yang 563 (HN); Binh Chau-Phuoc Buu Nature Reserve, Mar 2000, R K. Loc P10044, P10045 (HN). Binh ThuanTuy Phong District, Vinh Hao (11 [degrees]19'30" N, 108[degrees]49'37" E), Hill 5013, 20 May 1998 (NSW, HN, K, NY, PE, L). Khanh Hoa: Nha Trang and vicinity, Robinson 1304, 11-26 Mar 1911 (NY) [17 Nov 1913 - K]. Ninh Thuan: S of Ca Na, 10 Nov 1994, Yang 553, 555 (HN).

23. CYCAS SIAMENSIS Miq.

Cycas siamensis Miq., Bot. Zeitung (Berlin) 21: 334. 1863. Epicycas siamensis (Miq.) de Laub., in de Laub. & Adema, Blumea 43: 393. 1998. TYPE: Siam: J. E. Teysmann s.n., Mar. 1862 (HOLOTYPE: U, 2 sheets).

Cycas immersa Craib, Kew Bull. Misc. Inform. 1912: 434-435. 1912. TYPE: Laos: between Lakon and Phre, near Pang Pooey, alt. 420 m, Kerr 999 (HOLOTYPE: K, 2 sheets; ISOTYPE: BM). Although cited as Laos, this locality is within the present borders of Thailand.

Cycas cochinchinensis Warb. ex Schuster, Pflanzenr. 99: 81. 1932; nom. nud., in syn. Cycas siamensis.

Illustrations: Schuster (1932) Smitinand (1971); Wang (1996); Tang et al. (1997); Hill and Yang (1999).

Plant arborescent to acaulescent; stems to 1.5 m tall, 14-20 cm diam. Leaves bright green to deep green, semiglossy, 60-120 cm long, with white to orange to brown tomentum persistent above and below, flat (not keeled) in section (opposing pinnae inserted at 170-180[degrees] on rachis), with 140-280 pinnae, rachis frequently terminated by a spine 1-18 mm long. Petiole 11-31 cm long (15-30% of total leaf), pubescent, spinescent for 10-90% of length. Basal pinnae gradually reducing to spines, 10-50 mm long. Median pinnae simple, strongly discolorous, 80-145 mm long, 5-8 mm wide, inserted at 55-80[degrees] to rachis, decurrent for 2-4 mm, narrowed to 3-5 mm at base (to 50-70% of maximum width), 5-10 mm apart on rachis, section flat, margins slightly recurred; apex acute, spinescent, midrib flat above to raised above, raised below. Cataphylls linear, pungent, pilose, 60-70 mm long, persistent. Microsporangiate cones narrowly ovoid, orange to brown, 10-24 cm long, 5-7.5 cm diam. Microsporophyll lamina firm, not dorsiventrally thickened, 19-30 mm long, 11-17 mm wide, fertile zone 13-22 mm long, sterile apex 5-8 mm long, level, apical spine prominent, sharply upturned, 7-14 mm long. Megasporophylls 6-11 cm long, brown-tomentose; ovules 2, glabrous; lamina orbicular, 60-110 mm long, 30-80 mm wide, deeply pectinate, with 22-46 soft lateral spines 8-35 mm long, 1-2 mm wide, apical spine distinct from lateral spines, 23-45 mm long, 4-8 mm wide at base. Seeds subglobose, 30-37 mm long, 26-37 mm wide; sarcotesta yellow, not pruinose, 2-3 mm thick; fibrous layer present, or absent; sclerotesta smooth; spongy layer absent.

Distinguishing features: Cycas siamensis is distinguished by its flat leaves with a very short petiole and basal pinnae gradually reducing in size toward the spines. Megasporophylls are distinguished by being usually densely brown-tomentose, with the tomentum persisting around their bases and on the trunk around the persistent leaf bases. Microsporangiate cones are smaller than those of most of the C. pectinata complex and are of a distinct oblong shape. Its shortstemmed habit is also distinctive, plants reaching reproductive maturity before any aerial stem is developed. Another distinctive characteristic of C. siamensis is its sharply demarcated, bulbous base, often becoming broad and plate-like in older individuals. Seeds show variable development of the fibrous layer within the sarcotesta.

Distribution and habitat: Abundant in the central plateau region from Buon Ma Thuot to Pleiku (Dac Lac and Kon Tum), with a disjunct occurrence in Thanh Hoa and Nghe An Provinces in the north (Fig. 11). This species occurs in full sun to light shade in low, open woodland on flat country or on low hills, often in dense stands. Host woodland is often dominated by Dipterocarpus tuberculatus, with a wide range of associated trees such as Erythrina and Bombax. These woodlands are characteristically seasonally wet and dry with the monsoon weather patterns of the region, with particularly pronounced and extended dry periods. Cycas siamensis is widespread and abundant in similar habitats across the Indochinese peninsula, with the major populations mostly in Thailand.

Conservation status: A widespread and locally extremely abundant species. Although its habitat is continually being reduced, large populations remain, and it is not under any immediate threat of extinction. IUCN Red List status LR ed.

Selected specimens examined: VIETNAM. Nghe An: Nghia Dan, Nghia Hung, Qui Hop, 26 Oct 1994, Yang 528, 529 (HN). Dak Lac: Ea Sup (12[degrees]55'50" N, 107[degrees]48'30" E), 3 Nov 1994, Yang 538 (HN); Ea Sup, Buon Don, Don 3, near Campuchea, 17 Mar 1998, Hiep 2591 (HN).

THAILAND. Chachoengsao: Tha Takiap, N of village, Hill 4614, 14 Apr 1994 (NSW, BKF, K, L, PE). Chaiyaphum: Nong Bua Deng, Kerr 20299, 2 Mar 1931 (BM, K). Chonburi: Khao Khieo, Siricha District, Maxwell 75-237, 7 Mar 1975 (L). Hua Hin: Hua Hin, Kerr 16198, 11 Nov 1928 (BM, K). Kanchanaburi: Ban Sai Yok Noi, W of Kanchanaburi, Hill 4646, 03 May 1994 (NSW, BKF, K, L, PE). Lampang: Ban Mae Wang, Hosseus 361, 20 Jan 1905 (BM, K). Nakhon Ratchasima: Huai Thalaeng, Kerr PUT 2187, 21 Dec 1928 (BM, K). Phetchabun: Muang Lore Sak, Kerr 5737, 3 Apt 1922 (BM, K). Phrae: near Phrae, Yang 633, Tang & Vatcharakorn, 6 Feb 1995 (FTG). Ratchaburi: Thung Luang, W of the highway on Route 3337, Hill 4647, 03 May 1994 (NSW, BKF, K, L, PE). Sakon Nakhon: Ban Kusuman, Lashnakara 999, 25 Jun 1932 (BM, K). Tak: Ban Tak, N of Tak, Hill 4635, 24 Apr 1994 (NSW). Uthai Thani: near Kow Hin Dang station, Bahn Rai District, Maxwell 76-272, 22 Apr 1972 (L). Uttaridit: Ban Sore Bon, on Highway 11, Hill 4642, 29 Apr 1994 (NSW, BKF, K, L, PE).

MYANMAR. Pegu, Kurz 2622 (K).

CAMBODIA. Stoeng Treng, between Chap and Phumi Thalabarivat, Poilane 14249 (P); Kampong Thum, Pierre 532p.p., May 1870 (P); Pursat (?Pouthisat), Anlong Krauch, Martin 1374 (P).

C. Section CYCAS

Cycas section Lemuricae Schuster, Pflanzenr. 99: 65. 1932, nom. illegit.

Section Cycas is defined by its combination of glabrous ovules and nonpectinate megasporophyll lamina. Three subsections are recognized, circumscription following Hill (1995), with two occurring in Vietnam. The full range of the section is from India and southern Indochina southward to Australia and from East Africa eastward to Tonga.
Key to the Subsections

1. Seeds with a spongy layer inside the
   sclerotesta                                      Subsection Rumphiae
1. Seeds lacking a spongy layer
  2. Sarcotesta lacking a fibrous layer             Subsection Endemicae
     (Australia and New Guinea only,
      not discussed further)
  2. Fibrous layer present in seed sarcotesta           Subsection Cycas


C(i). Subsection CYCAS

This subsection of about 9 species is defined by the absence of a spongy layer, the presence of fibers in the sarcotesta, and its narrow megasporophyll lamina. It ranges from India and Sri Lanka to Luzon and southward and eastward to New Guinea. Most representatives are plants of closed forests, usually on ridges away from the coast. A single species occurs in Vietnam (Fig. 15).

[FIGURE 15 OMITTED]

24. CYCAS INERMIS Lour. (Figs. 16 & 17).

[FIGURES 16-17 OMITTED]

Cycas inermis Lour., Fl. Cochinch., ed. 2, 2: 776-777. 1793; Cycas revoluta vat. inermis (Lour.) Miq., Prodr. syst. Cycad.: 6, 16. 1861; Cycas siamensis subsp, inermis (Lour.) Schuster, Pflanzenr. 99: 80-81. 1932. TYPE: Vietnam: Saigon, 1787, Loureiro 3 holo (BM).

Cycas rumphii non Miq., sensu Leandri (1931), Ho (1991).

Cycas circinalis non L., sensu Hiep and Vidal (1996).

Stems arborescent; 1.5-4 m tall, 8-14 cm diam., 6-35 leaves in crown. Leaves deep green, highly glossy, 220-300 cm long, flat (not keeled) in section (opposing pinnae inserted at 180[degrees] on rachis), with 130-230 pinnae, with white tomentum shedding as leaf expands, rachis consistently terminated by paired pinnae. Petiole 65-80 cm long (25-35% of total leaf), glabrous, spinescent for 70-100% of length. Basal pinnae not gradually reducing to spines. Median pinnae simple, strongly discolorous, 250-350 mm long, 11-18 mm wide, inserted at 60-80[degrees] to rachis, decurrent for 5-7 mm, narrowed to 3-4.5 mm at base (to 20-30% of maximum width), 18-22 mm apart on rachis, section flat, margins flat to slightly recurved; apex softly acuminate, not spinescent; midrib raised above, flat below. Cataphylls linear, pungent, pilose, 40-50 mm long, articulated. Microsporangiate cones ovoid, cream, 12 cm long, 8 cm diam. Microsporophyll lamina firm, not dorsiventrally thickened, apical spine prominent, sharply upturned, ca. 10 mm long. Megasporophylls 20-30 cm long, gray-tomentose; ovules 4-8, glabrous; lamina ovate to lanceolate, 50-100 mm long, 30-65 mm wide, regularly dentate, with 14-26 pungent lateral spines 4-8 mm long, 1-1.5 mm wide, apical spine distinct from lateral spines, 20-30 mm long, 3-4 mm wide at base. Seeds oblong, 50-60 mm long, 38-50 mm wide; sarcotesta orange, slightly pruinose, 4-5 mm thick; fibrous layer present; sclerotesta smooth; spongy layer absent.

Typification: This specimen is of a leaf apex only (Fig. 16), but closely matches the forest species e.g. from Cat Tien National Park. Loureiro's description states that the megasporophyll is "laciniate," but no plant matching both the type (leaf) specimen and this megasporophyll description has been collected in Vietnam. It is possible that the description was a composite based on disparate specimens. For this study, the name "inermis" is applied to the inland forest species from south and central Vietnam that matches the type specimen. It is possible although unlikely that future discoveries may require a change to this nomenclatural application. Although named for the unarmed petiole, petiole spinescence varies, and wholly unarmed individuals are uncommon.

Distinguishing features: This species is readily distinguished within Vietnam by its narrow megasporophyll lamina with short lateral teeth and its seeds with a fibrous layer in the sarcotesta. It is nearest to Cycas macrocarpa from Thailand and Malaysia, differing in its shorter lateral spines on the megasporophyll.

Distribution and habitat: Widely distributed on the near-coastal ranges in central and southern Vietnam, from near Da Nang south to Nam Cat Tien National Park (Fig. 15). Locally common in closed evergreen or semideciduous forests on flat or elevated sites on granite, metamorphic or basaltic volcanic substrates. Cycas inermis often grows on steep slopes or local slight stony rises where the drainage would be greater.

Conservation status: Not considered to be at risk, although further study of distribution is required. IUCN Red List status DD/LR?

Selected specimens examined: VIETNAM. Dong Nai: Mt Pong Lu, Pierre 5517, May 1877 (P); Nam Cat Tien, Long s.n. (FIN). Khanh Hoa: high hills above Cam Ranh Bay, near Khanh Son road (11[degrees]57'24" N, 109[degrees]00'20" E), 19 May 1998, Hill 5008 (NSW, HN, K, L, MO, NY, P, PE). Quang Nam: Hai Van Pass, Hiep 4148, 4149, 4153 & Hill, 23 Jan 2000 (HN, NSW). Da Nang: Son Tra Nature Reserve, Hiep 4157 & Hill, 24 Jan 2000 (HN, NSW).

C(ii). Subsection RUMPHIAE K. D. Hill

Cycas subsection Rumphiae K. D. Hill, Austral. Syst. Bot. 7:548 (1994). TYPE: Cycas rumphii Miq., Bull. Sci. Phys. Nat. Neerl. 2:45 (1839).

This subsection is uniquely defined by the presence of a layer of spongy tissue within its seed. Another potentially synapomorphic character defining this group is the 2-year seed maturation period, although this has been confirmed only for Cycas seemannii, C. thouarsii, and C. bougainvilleana. All other species of Cycas for which data is available have a maturation period of less than one year.

Distribution is very wide, extending from Africa to Fiji and Tonga, and from New Guinea northward to southern coastal Indochina. One species occurs in Vietnam (Fig. 15).

Taxonomy of the group is difficult, and the exact number of species is unclear. All species in the Cycas rumphii complex have appeared in the literature erroneously as C. circinalis L. at some stage (discussed above, and see Hill, 1994).

The spongy layer causes seeds to be buoyant and has been proposed as a dispersal mechanism (Dehgan & Yuen, 1983). This dispersal mechanism has been interpreted as a cause of the taxonomic complexity of this group, with successive colonization events producing the high local variability in some populations and the very different forms sometimes occurring in close proximity (Fosberg & Sachet, 1975; Hill, 1994).

25. CYCAS LITORALIS K. D. Hill

Cycas litoralis K. D. Hill, in K. D. Hill & S. L. Yang, Brittonia 51: 70. 1998. TYPE: Thailand: Ao Manao Naol, Narathiwat, Hill 4627, 20 Apr 1994 (HOLOTYPE: NSW; ISOTYPE: BKF, K, L, PE).

Cycas circinalis non L., sensu Leandri (1931), Ho (1991).

Cycas rumphii non Miq., sensu Hiep and Vidal (1996).

Cycas edentata de Laub., in part, sensu de Laubenfels and Adema (1998).

Illustrations: Ridley (1925), as Cycas rumphii; Smitinand (1971), as Cycas rumphii; Tang et al. (1997); Hill and Yang (1999).

Plant arborescent; stems to 3(-10) m tall, 11-20 cm diam. Leaves bright green, highly glossy, 150-230 cm long, flat (not keeled) in section (opposing pinnae inserted at 180[degrees] on rachis), with 100-170 pinnae, tomentum shedding as leaf expands, rachis consistently terminated by paired pinnae. Petiole 50-90 cm long (30-50% of total leaf), glabrous, spinescent for 5-60% of length. Basal pinnae not gradually reducing to spines, 170-260 mm long. Median pinnae simple, strongly discolorous, 260-350 mm long, 14-19 mm wide, inserted at 65-80[degrees] to rachis, decurrent for 8-13 mm, narrowed to 6-8 mm at base (to 35-50% of maximum width), 15-35 mm apart on rachis, section flat, margins slightly recurved; apex acute, not spinescent; midrib flat above, raised below. Cataphylls narrowly triangular, soft, pilose, persistent. Microsporangiate cones narrowly ovoid, orange, 35-45 cm long, 13-17 cm diam. Microsporophyll lamina firm, not dorsiventrally thickened, 38 mm long, 21 mm wide, fertile zone 29 mm long, sterile apex 9 mm long, level, apical spine prominent, sharply upturned, 24 mm long. Megasporophylls 30-50 cm long, white-tomentose or yellow-tomentose; ovules 4-8, glabrous; lamina lanceolate, 90-120 mm long, 25-40 mm wide, obscurely dentate or regularly dentate, with 6-14 soft lateral spines 0-1 mm long, 0-1 mm wide, apical spine distinct from lateral spines, 25-40 mm long, 5-8 mm wide at base. Seeds flattened-ovoid, 52 mm long, 43 mm wide; sarcotesta orange-brown, not pruinose, 4 mm thick; fibrous layer absent; sclerotesta smooth; spongy layer present.

Distinguishing features: The nonpectinate megasporophyll and the large seed with spongy layer place this species unmistakably in the Cycas rumphii group. Within that group, it is distinguished from C. rumphii and all related species occurring to the south and east by its distinct, stout spines terminating the microsporophylls. Cycas thouarsii, from the southwestern Indian Ocean, shares the microsporophyll character but differs in having narrower pinnae that are distinctly glaucous when developing. Another Indian Ocean taxon presently known from Sri Lanka and the Andaman group that requires further investigation is characterized by longer, more abundant and distinctly pungent cataphylls with a more rufous tomentum. Cycas edentata de Laub. from the Philippines is distinguished by its extremely highly glossy leaves, more attenuate microsporophyll apices and reduced megasporophyll apices that are devoid of dentition. Relationships with C. edentata, however, require further study.

Distribution and habitat: Cycas litoralis occurs in southern Myanmar and southern Thailand, extending south into peninsular Malaysia and Sumatra, but apparently not elsewhere in Indonesia or Malaysia (Fig. 15). This species occurs only along shorelines, in full sun to moderate shade in often dry littoral scrubs on beach sand or rocky headlands, often in very shallow soil and apparently over both granite and limestone substrates. It is known from Phu Quoc island off the coast of southern Vietnam.

Conservation status: Once abundant and widespread, this species occurred in coastal sites that have experienced severe pressures from population increase and development. Although probably not immediately threatened, it is potentially vulnerable in the longer term. IUCN Red List status LRcd.

Selected specimens examined: VIETNAM. Kien Giang: near beach, W part of Phu Quoc island, leg. ign. (Botany Dept., Univ. Ho Chi Minh).

INDONESIA. Medan, N Sumatra, Lorzing 16881, 1934 (L); Kiorjoh, Enggano, Lutjeharms 4691, 13 Jun 1936 (K, L).

MALAYSIA. Pulau Tioman, Lee s.n., 28 May 1974 (BKF); Perak, Ridley 7143, Mar 1896 (K); Padang Mulut, SE Johore, Shah & Shukor MS 2480, 19 Sep 1971 (BKF).

THAILAND. Chumphon: Ko Tao, Kerr 12768, 16 Apr 1927 (BM, K), 16087, 25 Sep 1928 (K). Narathiwat: Narathiwat, Charoenphol, Larsen & Warncke 4064, 20 Oct 1970 (BKF, 14). Phang Nga: Takuapa, Abbe, Smitinand & Roller 9684, 19 Mar 1960 (NY); Ko Ngai, Hansen & Smitinand 12242, 11 Feb 1966 (BKF, K). Trat: Ko Chang, Kerr 16569, 10 Jan 1929 (BM, K).

VIII, Species Known from China That May Be Expected to Occur in Vietnam

A. CYCAS SEGMENTIFIDA D. Y. Wang & C. Y. Deng

Cycas segmentifida D. Y. Wang & C. Y. Deng, Encephalartos 43: 11. 1995. TYPE: Cult. in South China Botanical Garden, Guangzhou, China, D. Y. Wang & H. Peng 2967, 16 May 1994 (HOLOTYPE: SZG; ISOTYPE: FTG n.v., GZAC n.v., NF n.v., NSW, X1N n.v.).

Cycas longiconifera H. T. Chang, Y. C. Zhong & Y. Y. Huang, Acta Sci. Nat. Univ. Sunyatseni 37: 6. 1998. TYPE: China: Guangxi, Baise, alt. 850 m, in calceo-saxo, Y. C. Zhong 8771, 26 Mar 1998 (HOLOTYPE: SYS).

Cycas multifida H. T. Chang & Y. C. Zhong, Acta Sci. Nat. Univ. Sunyatseni 36: 70. 1997. TYPE: China: Guangxi:Xiling, in arenoa-saxa, alt. 780 m, Y. C. Zhong 80196, 27 Jun 1995 (HOLOTYPE: SYS).

Cycas xilingensis H. T. Chang & Y. C. Zhong, Acta Sci. Nat. Univ. Sunyatseni 36: 69. 1997. TYPE: China: Guangxi: Xiling, alt. 880 m, Y. C. Zhong 80866, 18 Jul 1994 (HOLOTYPE: SYS).

Literature: Chen and Stevenson (1999).

Illustrations: Wang (1996).

Stems arborescent to acaulescent, to 0.5 m tall, 10-23 cm diam. at narrowest point, 8-25 leaves in crown. Leaves' deep green, highly glossy, 120-280 cm long, flat (not keeled) in section (opposing pinnae inserted at 180[degrees] on rachis), with 80-190 pinnae, with orange tomentum shedding as leaf expands; rachis consistently terminated by paired pinnae. Petiole 40-140 cm long (30-50% of total leaf), glabrous, spinescent for 90-100% of length. Basal pinnae not gradually reducing to spines, 70-290 mm long. Median pinnae simple, strongly discolorous, 120-420 mm long, 9-20 mm wide, inserted at 50-80[degrees] to rachis, decurrent for 4-7 mm, narrowed to 3-7 mm at base (to 30-50% of maximum width), 11-24 mm apart on rachis; section flat; margins flat; apex acute, not spinescent; midrib raised above, raised below. Cataphylls narrowly triangular, soft, pilose, 70-100 mm long, persistent. Microsporangiate cones fusiform, yellow, 30-60 cm long, 5-12 cm diam. Microsporophyll lamina soft, not dorsiventrally thickened, 20-30 mm long, 15-18 mm wide, fertile zone 17-27 mm long, sterile apex 3 mm long, level, apical spine absent. Megasporophylls 16-25 cm long, yellow-tomentose or browntomentose; ovules 4-8, glabrous; lamina orbicular, 80-130 mm long, 50-120 mm wide, deeply pectinate, with 16-44 soft lateral spines 20-70 mm long, 2-3 mm wide, apical spine distinct from lateral spines, 25-125 mm long, 8-20 mm wide at base. Seeds subglobose, 28-35 mm long, 24-30 mm wide; sarcotesta yellow, not pruinose, 1.5 mm thick; fibrous layer absent; sclerotesta verrucose; spongy layer absent.

Distinguishing features: Within the group of Chinese cycads with soft microsporangiate cones, loose, freely peeling sarcotesta lacking a fibrous layer, and rugose sculpting of the sclerotesta (Section Stangerioides), this species is distinguished by its small seeds, broad pinnae with flat or undulate margins, pinnae that are flat and not twisted on the rachis, and large megasporophyll apex with a broad apical spine.

Distribution and habitat: Once an extremely widespread species through western Guangxi, extending into southern Guizhou and eastern Yunnan, in both cases to a limited extent. This species occurs on a range of substrates from limestone to shale and schist, usually on steep slopes lower in valleys with some, though often skeletal, soil cover. Vegetation ranges from closed evergreen forest to mixed deciduous and evergreen woodland, although today it is mostly severely degraded to grassland or scrubby secondary regrowth.

Conservation status: This species is moderately abundant over a considerable area in western Guangxi Province but is now severely depleted. There is, however, no immediate threat of extinction.

Selected specimens examined: CHINA. Guangxi: Ba Gen village, 5 km from Debao city (23[degrees]21'52" N, 106[degrees]39'44" E), Chen, Zhong & Hill 07, 9 Nov 1998 (BKF, HN, K, NY, P, PE); Side road from main Debao to Baise road (23[degrees]36'18" N, 106038'43" E), Chen, Zhong & Hill 09, 10, 9 Nov 1998 (NSW, PE); Yan Ron locality, Wei Hua village, Le Li town, 10 km SW of Tianlin city (24[degrees]15'44" N, 106[degrees]11'17" E), Chen, Zhong & Hill 11, 12, 10 Nov 1998 (NSW, PE); Fu Da town, S of Tian Lin city (24[degrees]21'18" N, 105[degrees]51 '13" E), cult. in town, coll. from nearby, Chen, Zhong & Hill 15, 11 Nov 1998 (NSW, PE); Long Lo Tun locality, Po Ning village, Ba Da town, ca. 3 km SE of Xilin city (24[degrees]28'21" N, 105005'34" E) alt. 820 m, type locality for Cycas xilingensis, Chen, Zhong & Hill 17, 12 Nov 1998 (NSW, PE); Zhou Bong village, ca. 9 km NE of Xilin city (24[degrees]32'57" N, 105[degrees]06'39" E), alt. 920 m, type plant of C. multifida, Chen, Zhong & Hill 18, 12 Nov 1998 (NSW, PE); Zu Be town, ca. 3 km SE of Xilin city (24016'00" N, 105[degrees]26'48" E), alt. 680 m, Chen, Zhong & Hill 19, 13 Nov 1998 (NSW, PE); Liu Long Guo, near Bian Ya town, E of Longlin city (24[degrees]43'04" N, 105[degrees]28'13" E), alt. 720 m, Chert, Zhong & Hill 20, 15 Nov 1998 (NSW, PE).

B. CYCAS DIANNANENSIS Z. T. Guan & G. D. Tao

Cycas diannanensis Z. T. Guan & G. D. Tao, Sichuan Forestry & Desig., 1995: 1. 1995. TYPE: China: Yunnan: S. Gejiu County, Manhao, alt. 700-1120 m, G. D. Tao 95014 (HOLOTYPE: I??).

Cycas parvulus S. L. Yang, in D. Y. Wang, Cycads in China: 93. 1996. TYPE: China: Yunnan: around Mengdian village, Honghe County, 5 km from Yuanjiang [River], S. L. Yang 317 (HOLOTYPE: HWA; ISOTYPE: FTG, PE).

Cycas pectinata var. manhaoensis C. Chen & P. Yun, Acta Bot. Yunnan. 17: 400. 1995. TYPE: China: Yunnan: Gejiu, Manhao, alt. 1210 m, M. C. Cai & P. Yun 22, 19 Jun. 1995 (HOLOTYPE: YUN).

Literature: Wang (1996), and as Cycas parvulus.

Illustrations: Wang (1996), and as Cycas parvulus.

Stems arborescent or acaulescent, to 3 m tall, 25-35 cm diam. at narrowest point, 12-50 leaves in crown. Leaves bright green or deep green, highly glossy, 140-330 cm long, slightly keeled or fiat (not keeled) in section (opposing pinnae inserted at 160-180[degrees] on rachis), with 160-300 pinnae, with white or orange tomentum shedding as leaf expands; rachis terminated by a spine 1-11 mm long or paired pinnae. Petiole 45-100 cm long (20-30% of total leaf), glabrous, spinescent for 90-100% of length. Basal pinnae not gradually reducing to spines, 30-240 mm long. Median pinnae simple, strongly discolorous, 130-320 mm long, 9-16 mm wide, inserted at 50-80[degrees] to rachis, decurrent for 3-7 mm, narrowed to 2.5-4 mm at base (to 20-30% of maximum width), 10-20 mm apart on rachis; section fiat; margins slightly recurred; apex acute, not spinescent; midrib raised above, raised below. Cataphylls linear, pungent, thinly sericeous or lacking tomentum, 120-200 mm long, persistent. Pollen cones narrowly ovoid, yellow, 50-65 cm long, 9-13 cm diam. Microsporophyll lamina soft, not dorsiventrally thickened, 35-60 mm long, 15-25 mm wide, fertile zone 30-50 mm long, sterile apex 4-10 mm long, raised, apical spine rudimentary, sharply upturned, 0-2 mm long. Megasporophylls 16-24 cm long, graytomentose; ovules 4-8, glabrous; lamina orbicular or ovate, 65-140 mm long, 55-140 mm wide, deeply pectinate, with 30-52 soft lateral spines 10-50 mm long, 1.5-4 mm wide, apical spine distinct from lateral spines, 10-45 mm long, 7-15 mm wide at base. Seeds ovoid, 28-40 mm long, 20-32 mm wide; sarcotesta yellow, not pruinose, 3-4 mm thick; fibrous layer absent; sclerotesta verrucose; spongy layer absent.

Distinguishing features: Within the group of Chinese cycads with soft microsporangiate cones, loose, freely peeling sarcotesta lacking a fibrous layer and rugose sculpting of the sclerotesta (Section Stangerioides), this species is distinguished at once by its very long, prominent, and pungent cataphylls and also by its small seeds, broad pinnae with flat or undulate margins, pinnae that are flat and not twisted on the rachis, and large megasporophyll apex with a broad apical spine.

Distribution and habitat." A widespread species through central and eastern Yunnan, along the Hong He Valley between Hekou and Shuangbai. This species occurs on a range of substrates from limestone to shale and schist, usually on steep slopes high on ridges, between about 600 and 1800 m. Original vegetation was closed evergreen forest in the cloud zone, although today it is often severely degraded to grassland or scrubby secondary regrowth. This species is reported from Da Wei Shah Nature Reserve (Hekou County), and also from near Malipo (Maguan County), both quite close to the Vietnam-China border.

Conservation status." This species is moderately abundant over a considerable area in central and eastern Yunnan Province, but many populations are now depleted. There is, however, no immediate threat of extinction.

Selected specimens examined: CHINA. Yunnan: Gejiu County, Manhao, cult. in power station, Hong 369, 370, Chen, Hill & Stevenson, 6 Jul 2000 (YUN, NSW, NY, PE); Gejiu County, Manhao, wild, 1250 m, Hong 371, 372, Chen, Hill & Stevenson, 7 Jul 2000 (YUN, NSW, NY, PE); Juanjiang County, cult. in Yuanjiang power station, Hong 408, 409, Chen, Hill & Stevenson, 15 Jul 2000 (YUN, NSW, NY, PE); Xinping County, Yiao Jie, cult. in hospital garden, coll. nearby, Hong 410, 411, Chert, Hill & Stevenson, 16 Jul 2000 (YUN, NSW, NY, PE); Xinping County, Shui Tang, cult. in school garden, coll. nearby, Hong 412, Chen, Hill & Stevenson, 16 Jul 2000 (YUN, NSW, NY, PE); Xinping County, Ga So, wild, Hong 229, 12 Dec 1999 (YUN); Shuang Bai County, Li et al. 2216, 23 Apr 1999 (YUN).

IX. Doubtful and Excluded Names

Cycas bellefontii L. Linden & Rodigas, Ill. hortic. 33: 27, planche 586. 1886; as bellefonti. TYPE: The plate, planche 586 in Ill. hortic. 33. 1886, has been accepted as the type (de Laubenfels & Adema, 1998). This plate clearly shows numerous leaves with relatively broad pinnae tapering more or less equally toward both base and apex. This condition is not found in any known Vietnamese species, and may be an artifact of the illustration. The plate therefore cannot be matched unequivocally with any known species; in the absence of a type specimen, the name must be excluded.

Cycas longipetiolula D. Y. Wang, Cycads China: 68. 1996. TYPE: China: Yunnan: Yuanjiang River valley, D. Y Wang & H. Peng 5523, 23 Apr 1994 (HOLOTYPE: SZG; ISOTYPE: NF). Cycas multipinnata is apparently sympatric with C. bifida in several populations in China, and a range of morphologically intermediate forms that can be interpreted as a hybrid swarm has been observed. The type of C. longipetiolula is one such form.

Cycas miquelii Warb., Monsunia 1 : 179, 184. 1900; Epicycas miquelii (Warb.) de Laub., in de Laub. & Adema, Blumea 43: 393. 1998. TYPE: "Ex horto Buitenzorg (ex China & Japonic.) in H. Amstelod. introducta" (syn. U 028127, U 028129). No type was cited, and the distribution was cited only as "Slid-China." However, Warburg refers to specimens in Miquel's herbarium, from a plant cultivated in the Amsterdam botanic garden that had been brought in from the Bogor botanic garden and was said to be from South China. Miquel had incorrectly determined and illustrated these as C. inermis (Miquel, 1851). These would appear to be the basis for C. miquelii, and hence acceptable as types. These specimens are clearly a somewhat aberrant C. revoluta lacking petiolar spines, and C. miquelii must thus fall into the synonymy of C revoluta. Neotypification by de Laubenfels and Adema (1998) is based on a specimen of a quite different species from southern Thailand (C. clivicola, see above). This is redundant when the above is taken as the type. It is also in conflict with the protologue because it is not from southern China.

Cycas multifrondis D. Y. Wang, Cycads China: 80. 1996. TYPE: Cult. in Xiamen Botanical Garden, D. Y. Wang 5024, 28 Jun 1994 (HOLOTYPE: SZG; ISOTYPE: NF). The type specimen is from one of a few plants in cultivation, of uncertain provenance. These plants are characterized by a larger number of leaves, larger megasporophylls, and leaflets with fewer divisions or sometimes entire. They are thought to represent hybrids between C. bifida and a simply pinnate species. The larger megasporophylls suggest C. segmentifida as the second parent.

Cycas tonkinensis (L. Linden & Rodigas) Rodigas, Ill. hortic. 33: 27. 1886; Zamia tonkinensis L. Linden & Rodigas, Ill. Hortic. 32: Planche 547. 1885; Epicycas tonkinensis (L. Linden & Rodigas) de Laub., in de Laub. & Adema, Blumea 43:391.1998. TYPE: The plate, planche 547 in Ill. hortic. 32 (1885), has been accepted as the type (de Laubenfels & Adema, 1998). This plate clearly shows numerous short leaves with very broad pinnae tapering more or less equally toward both base and apex. This condition is not found in any known Vietnamese species and may be an artifact of the illustration. The plate therefore cannot be matched unequivocally with any known species; in the absence of a type specimen, the name must be excluded. De Lanbenfels and Adema (1998) have used the name C. tonkinensis as a "catch-all" for all acaulescent species from southern China and Indochina, including C. balansae, C. chevalieri, and C. simplicipinna in the above account. It should be noted that C. fugax has leaflets that match the C. tonkinensis illustration and description in width and profile, but C. fugax has much longer leaves and especially petioles and never develops the number of leaves shown in the plate.

Cycas undulata Desf. ex Gaudich., Voy. Uranie, Bot.: 434. 1829; Desf., Tabl. Ecole Bot. ed. 3, 29. 1829, nom. nud.; Cycas circinalis [subsp. circinalis] forma undulata (hort. ex Gaudich.) Schuster, Pflanzenr. 99: 66. 1932; Cycas rumphii forma undulata (Desf. ex Gaudich.) Kanehira, J. Jap. Bot. 14(9): 587. 1938. TYPE: Hort. Paris, 1820, ex herb. Houllet (HOLOTYPE: P). This specimen is of a developing leaf of C. circinalis. The name C. undulata has been applied to a variety of taxa, including some from Vietnam (Schuster, 1932). The above typification clearly establishes C. undulata as a synonym of C. circinalis, an Indian endemic.

X. Acknowledgments

The Hermon Slade Foundation is warmly thanked for the financial support that allowed this study to proceed. The Vietnamese Institute of Ecology and Biological Resources in Hanoi and Ho Chi Minh City, and Mr. V. N. Long of that institution in Ho Chi Minh City, are thanked for assistance with access for field studies and with specimen handling. Kampon Tansacha and the Nong Nooch Tropical Garden are gratefully acknowledged for hospitality and logistical assistance. Anders Lindstrom has assisted in the field and in valuable discussions of the taxonomic and distributional limits of the cycads of Asia. Bui Xuan Chuong and Lesley Elkan are thanked for the illustrations, and Peter Wilson is thanked for assistance with Latin diagnoses. The keepers of the herbaria B, BKF, BM, K, L, NY, and P are acknowledged for access to their collections of Asian material.

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KEN D. HILL

National Herbarium of New South Wales

Royal Botanic Gardens

Sydney 2000, Australia

HIEP T. NGUYEN

Institute of Ecology and Biological Resources

Nghia Do, Cau Giay, Hanoi, Vietnam

AND

PHAN K. Loc

Department of Botany

University of Science, VNU

Thanh Xuan, Hanoi, Vietnam
Table I
Conservation status of Vietnamese cycads

                                  Reserved

                   Occurrence   1997    IUCN
                    outside     Red     1994     Population    Present
Cycas species       Vietnam     List   status       size       decline

C. aculeata                            VU/CR?     ?250-2500     ?low
C. balansae          China       y      LRnt       >10,000       low
C. brachycantha                  y      LRnt       >10,000       low
C. chevaliers        ?Laos       y      LRnt       >10,000       low
C. clivicola       Cambodia,            LRnt       >10,000       low
                   Malaysia,
                    Thailand
C. collina           ?Laos             VU A2c    2500-10,000     low
C. condaoensis                   y      VU D2    2500-10,000   stable
C. dolichophylla     China       y     VU A2c      >10,000       low
C. elongata                            VU A2c      >10,000      high
C. ferruginea                    y      LRnt       >10,000       low
C. fugax                               DD/CR?     ?250-2500     high
C. hoahinhensis                  y     EN A2c    2500-10,000    high
C. inermis                       y     DD/LR?      >10,000      high
C. lindstromii                         VU A2c      >10,000      high
C. litoralis       Indonesia,           LRcd       >10,000       low
                   Malaysia,
                    Thailand
C. micholitzii                   y     VU A2c      >10,000      high
C. multipinnata      China              DD/CR     1000-2500      low
C. sexseminifera     China       y      LRnt       >10,000       low
C. bifida            China       y     VU A2c      >10,000      high
C. pachypoda                           DD/LR?    2500-10,000     low
C. pectinata         China,      y     VU A2c      >10,000       low
                     India,
                     Laos,
                    Thailand
C. siamensis       Thailand,     y     VU A2c      >10,000       low
                    Cambodia
C. simplicipinna   Thailand,     y      LRnt       >10,000       low
                     Laos,
                    Myanmar
C. tanquingii        China       N       NT       >100,000     stable
C. tropophylla                   y      LRnt       >10,000       low

                   Range    Habitat
Cycas species      (km)    reduction

C. aculeata         20      ?20-50
C. balansae         400      20-50
C. brachycantha     50
C. chevaliers       100      20-50
C. clivicola       1000       <20
C. collina          200      20-50
C. condaoensis      20        -20
C. dolichophylla    500      20-50
C. elongata         100      20-50
C.,ferruginea       50
C. fugax            200       ?80
C. hoahinhensis     50       50-80
C. inermis          200      20-50
C. lindstromii      200
C. litoralis       1000      20-50
C. micholitzii      200      20-50
C. multipinnata    ?300      20-50
C. sexseminifera    500
C. bifida           100      20-50
C. pachypoda        20
C. pectinata                 20-50
C. siamensis       1000      20-50
C. simplicipinna   1000      20-50
C. tanquingii       100       <20
C. tropophylla      50        <20

Table II
The Cycas simplicipinna complex

Distinguishing feature      C. simplicipinna    C. collina

Stem diameter, em                 8-14             10-18
Leaf length, cm                  90-250           180-330
Petiole length, can              35-140           70-190
No pinnae                        35-80            120-180
Pinna length x width, mm     20-60 x 14-20    280-410 x 17-23
Pinna spacing, mm                20-40             17-25
Microsporangiate cone        15-21 x 2.5-4      25-35 x 7-9
  length x diameter, cm
Megasporophyll length, cm         7-12             8-14
Apical spines, mm                15-25              30

Distinguishing feature         C. fugax

Stem diameter, em                8-12
Leaf length, cm                 280-400
Petiole length, can             150-220
No pinnae                       70-110
Pinna length x width, mm    420-500 x 19-31
Pinna spacing, mm                30-40
Microsporangiate cone        10-12 x 2.5-5
  length x diameter, cm
Megasporophyll length, cm        20-24
Apical spines, mm               40-100
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Author:Hill, Ken D.; Nguyen, Hiep T.; Loc, Phan K.
Publication:The Botanical Review
Geographic Code:9VIET
Date:Apr 1, 2004
Words:25242
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