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Nombres validos para hibridos del complejo Andropogon lateralis (Poaceae, Andropogoneae) sobre la base de analisis multivariados.

NAMING HYBRIDS IN THE ANDROPOGON LATERALIS COMPLEX (POACEAE, ANDROPOGONEAE) AFTER MULTIVARIATE ANALYSES

INTRODUCTION

The Andropogon lateralis Nees complex in southern South America (Argentina, Bolivia, Brazil, Paraguay and Uruguay) is represented by the following species: A. arenarius Hack., A. bicornis L., A. glaziovii Hack., A. hypogynus Hack., A. lateralis Nees, and the hybrids A. x coloratus (Hack.) (pro. sp.), A. x lindmanii (Hack.) (pro. sp.), A. x subtilior (Hack.) Norrmann, A. arenarius x A. bicornis and A. bicornis x A. glaziovii. The first two hybrids have variable degrees of fertility, and the others are completely sterile (Norrmann, 2009). The complex is considered to be a natural group of alohexaploid species (2n = 6x = 60), in which anther size and the number of pollen grains in the fertile sessile spikelets are strongly reduced compared with those of pedicellate spikelets. This discriminant character "dimorphism of anthers" defines the complex (Campbell, 1983; Campbell & Windisch, 1986).

Within this complex, natural inter-specific hybrids have been reported, where populations of different species live in sympatry. Three hybrid combinations were reported by Campbell & Windisch (1986) and two more by Norrmann (2009). Of the ten taxa that the complex comprises in southern South America, five are legitimate species and the others are inter-specific hybrids, of which three have taxonomically valid names: A. x coloratus, A. x lindmanii and A. x subtilior (Norrmann, 2009).

During the treatment of inter-specific hybrids within the complex, one of the authors of this work proposed taxonomic names for most hybrids (Norrmann, 2009). Therefore, natural hybrids between A. hypogynus and A. lateralis were added to the already existing entity A. x coloratus; in the same way natural hybrids between A. arenarius and A. lateralis were included in A. x lindmanii, and those between A. bicornis and A. lateralis in A. x subtilior.

Since then, different analyses were performed on these hybrids, including inflorescence typology and morphometric analyses, confirming the consistency of these entities (Nagahama, 2012). Therefore, we propose that both unnamed natural hybrids remaining in Norrmann (2009) treatment also deserve a name. The aims of this study are to: (1) analyze hybrid combinations based on characters of the inflorescences, (2) propose taxonomic names of two hybrid combinations as in other cases within the complex and (3) present the taxonomic treatment of A. arenarius x A. bicornis and A. bicornis x A. glaziovii.

MATERIALS AND METHODS

Plant material

We analyzed the following taxa: A. arenarius, A. bicornis, A. glaziovii, A. bicornis x A. glaziovii and A. arenarius x A. bicornis. We used the living collection of Andropogon species and hybrids held at IBONE, Corrientes, Argentina. Additionally, collection trips were undertaken since April 2007 to 2010, covering north-eastern Argentina (Corrientes, Chaco, Formosa, Misiones, Santa Fe), Brazil (Rio Grande do Sul, Santa Catarina), and Paraguay (Fig. 1). To identify a specimen as a natural hybrid, putative parents should be present at the field collection sites. Each field collection from natural populations included live individuals and synflorescences. Plants were transplanted to clay pots at the experimental garden of the Instituto de Botanica del Nordeste (IBONE), Corrientes, Argentina, where individuals from each species and hybrid combination were cultivated. Vouchers were deposited at the CORD herbarium and other voucher specimens from CTES, CORD, MI, VI were analyzed. More details of species and hybrids can be found in Norrmann (2009) and Nagahama (2012).

Morphometric analysis

Eighteen quantitative characters (see Table 1) of 130 specimens (species and hybrids) were analyzed on the basis of the correlation matrix through Principal Components Analysis (PCA) using the Pearson correlation coefficient (Michener & Sokal, 1957) and the data matrix (data not show) was standardized by character using PC-ORD program v. 4.25 (McCune & Mefford, 1999). We excluded from the analysis both the first pair of spikelets (due to its variability) and the terminal sessile spikelet (because of the truncation) of each floriferous branch (Nagahama, 2012). To reduce the experimental error, we considered the variability of the spikelets within the same plant. To do this, 10 pairs of spikelets were measured per plant and average values were used for morphometric analyses. Also, floriferous branches were selected from different branches of each plant and in turn, this methodology was carried out in at least 22 up to 30 individuals per entity of different populations, depending on availability of material.

[FIGURE 1 OMITTED]

The electronic version of this article in Portable Document Format (PDF) will represent a published work according to the International Code of Nomenclature for algae, fungi, and plants, and hence the new names contained in the electronic version are effectively published under the Code from the electronic edition alone. The online version of this work is archived and available from Instituto de Botanica Darwinion and the digital repositories cited in

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RESULTS

Specimens of A. bicornis, A. glaziovii and their hybrids formed three well defined groups, with the hybrids positioned between A. bicornis and A. glaziovii groups (Fig. 2). The first component explains 54.2 %, the second 20.3 %, and the third 6.7 % of the total variance. The variables that contribute most to the first component (and their eigen values) are length of hairs on articulated rachis internodes (-0.30), length of hairs on pedicel (0.30), pedicellate spikelet width (-0.29), pedicellate spikelet length (0.28), length of articulated rachis internodes (-0.28), pedicel length (-0.28) and pedicel width (0.28), while the length of first branch on the main axis of synflorescence (-0.44), number of branches on the first branch (-0.40), number of branches on the main axis of synflorescence (-0.38) and synflorescence length (-0.37) contributes to the second component.

Figure 3 shows specimens of A. arenarius, A. bicornis and their hybrids. The hybrids are positioned between the parental species. The first component explains 65.9 %, the second 11.9 %, and the third 5.9 % of the total variance. The variables number of internodes of the second branch (-0.28), length of second branch on the main axis of synflorescence (-0.27), number of branches on the first branch (-0.27), number of internodes of the first branch (-0.27), length of first branch on the main axis of synflorescence (-0.27), number of internodes of the main axis of synflorescence (-0.27), pedicel width (-0.27) and number of branches on the main axis of synflorescence (0.26) contribute more to the first component. On the other hand, the variables that contribute most to the second component are length of hairs on articulated rachis internodes (0.49), sessile spikelet length (0.41), pedicel length (-0.38), length of articulated rachis internodes (-0.30) and sessile spikelet width (-0.28).

[FIGURE 2 OMITTED]

When analyzing two species together with their corresponding hybrid combination (Figs. 2 and 3), there were three well-defined groups, indicating that the hybrids have stable morphotypes and that these are identifiable in the sympatric areas of the parental species.

DISCUSSION AND CONCLUSIONS

Among the five inter-specific natural hybrids recognized up to date in the A. lateralis complex, three were described in the past at species level: A. x coloratus, A. x lindmanii and A. x subtilior. Nowadays these hybrids are considered as legitimate taxonomic entities, as they are morphologically distinct from their parental species, being useful to have them formally named (Norrmann, 2009). However the hybrid combinations A. bicornis x A. glaziovii and A. arenarius x A. bicornis did not receive names in the past, likely because they were no collected at all during the lifetime of E. Hackel.

Most hybrid combinations in A. lateralis complex are sterile due to complete failure to form embryo sacs (A. x subtilior , A. arenarius x A. bicornis and A. bicornis x A. glaziovii; Norrmann, 2009). In both cases analyzed in this study (sterile inter-specific hybrids), the analysis by PCA showed three defined groups (Figs. 2 and 3) due to the absence of backcrossing, enabling the identification of hybrids which present stable morphotypes. Those morphotypes presented differences in both inflorescence typology (Nagahama, 2012) and morphometric analysis of inflorescences, allowing us to recognize these specimens into the complex by classical means. In addition, hybrid individuals generally flower together and live together. Considering all these facts, these hybrids could be considered as 'good species' in the classical topological taxonomic sense (Cronquist, 1981) and they deserve to be classified and formally named as other hybrids in the complex.

TAXONOMIC TREATMENT

Andropogon x velutinus Norrmann & Nagahama, nothosp. nov. (= A. bicornis x A. glaziovii). TYPE: Paraguay, Depto. Concepcion, 38 km E de Concepcion por ruta 5, 20-IV1995, G. A. Norrmann 219 (holotype CORD!; isotype CTES). Fig. 4.

Plants perennial, cespitose, culms 120-220 cm tall, nodes 17-27, glabrous; floral stem robust, cylindrical. Leaf sheaths generally longer than the internodes, velvety rarely glabrous; blades 26-74 x 0.3-0.6 cm, not basally constricted, linear, usually conduplicate, pubescent on both surfaces, rarely glabrous, margins scabrous towards the apex, acute apex; ligule 0.5-1 mm long, membranousciliate. Inflorescence a false panicle, 120.1-220 cm long, corymbosus, highly branched, especially in the upper nodes, composed of both terminal and axillary inflorescence units, these units 3-4.1 cm long, with 2, rarely 3 racemes, equal or subequal in length, conjugate or subdigitate, exserted or partially enclosed by the spatheole; peduncle of the inflorescence unit 1.6-6 cm long; spatheoles 2-5.5 cm long. Pedicels and rachis internodes linear, subequal in length, pedicels 1.6-2.8 mm long, internodes from 1.9-3 mm long, both with hairs 5.3-8.2 mm long. Sessile spikelets perfect, 3-4.1 x 0.8-1 mm, linear-lanceolated, generally awned, callus shortly pubescent, hairs 1-1.5 mm long. Lower glume 3-4 x 0.5-0.7 mm, slightly concave, lanceolate, chartaceous, margins glabrous, 2nerved, acute apex; upper glume 2.6-3.1 x 0.7-1 mm, chartaceous, margins glabrous, 3-nerved, the lateral nerves tenuous, acute apex. Lower lemma 1.8-2 x 0.5-0.7 mm, bicarenate, lanceolate, hyaline, glabrous, 0-3-nerved, acuminate apex; palea absent; upper lemma 1-2 x 0.1-0.6 mm, hyaline, glabrous on the margins, 1-nerved, acute apex, awned, awn 5-9 mm long; palea 0.6-0.9 x 0.2-0.5 mm, hyaline, glabrous , 0-nerved, erose apex. Lodicules 2, 0.4 mm long, glabrous. Stamens 3, anthers 0.5-0.8 mm long, yellow. Cariopsis not developed or undeveloped 0.9-1.9 x 0.3-0.5 mm. Pedicellate spikelets usually reduced, 0.5-1 x 0.05 mm long. Pedicelled spikelet of the penultimate pair developed, male, 3-4.5 x 0.1-0.2 mm long, lanceolate, awnless, with 3 stamens, anthers 1-1.5 mm long. Lower glume 2.8-4 x 0.5-1 mm, subchartaceous, glabrous on the margins, 5-nerved, acute apex; upper glume 2-3.3 x 0.8-1 mm, chartaceous, glabrous, 3-nerved, acute apex; lower lemma 2-3 x 0.6-1 mm, hyaline, 3-nerved; palea absent; upper lemma 1.9-2.7 x 0.5-0.7 mm, hyaline, 1-nerved; palea 0.6-0.8 x 0.1-0.2 mm long, hyaline, glabrous, 0-nerved, erose apex. Lodicules 2, 0.5 mm long, glabrous, anthers 1.1-1.5 mm long.

[FIGURE 3 OMITTED]

Distribution and habitat. Andropogon x velutinus grows in west-central and southeastern Brazil, and Paraguay, forming small but dense populations in confined sympatric areas--swamps-among populations of the parental species (A. bicornis and A. glaziovii). Parental species A. bicornis grows from the southern United States to northern Argentina and A. glaziovii is restricted to Paraguay, Bolivia and west-central and southeastern Brazil (Goias, Mato Grosso do Sul, Mina Gerais and Sao Paulo).

Observations. Andropogon x velutinus (= Andropogon sp 1 according to Zanin, 2001) is a sterile alohexaploid (2n = 6x = 60).

Representative examined material

Andropogon bicornis L.

ARGENTINA. Chaco. Depto. 1 de Mayo, Colonia Benitez, borde de estero, 20-IV-1965, Schulz 15022 (CTES); 17-IV-1964, Schulz 13841 (CTES). Corrientes. Depto. Bella Vista, 15 km N de Bella Vista, 16-V-1983, Norrmann & Quarin 89 (CTES); Depto. Capital, 18 km SE de Corrientes, Ruta 5, 25-III-1982, Norrmann 51 (CTES, LIL); Riachuelo, 7-IV-1974, Quarin 2344 (CTES); Campus Universitario, 20-III 1998, Schinini 34389 (CTES); Mansion de Invierno, 20-IV-1972, Carnevali 3044 (CTES); ruta 12 y Arroyo Riachuelo, 1-III-1995, Schinini 29131 (CTES). Depto. General Alvear, ruta 14 y Rio Aguapey, 17-V-1983, Norrmann & Quarin 91 (CTES, BAA, US). Depto. Itati, ruta 12, 47 km. E de Itati, 26-II-1977, Ahumada 775 (CTES); Puerto Corazon, 5 km. N de ruta 12, 17II-1983, Schinini & Carnevali 23268 (CTES). Depto. Ituzaingo, ruta 12 y ruta 38, al costado del camino, 24-VI-1990, Schinini 26868 (CTES); desembocadura del Arroyo Garape en el Rio Parana, 24-IV-1975, Schinini 11093 (CTES); Isla Apipe Grande, Puerto San Antonio, 10-XII-1973, Krapovickas 24122 (CTES); 9 km. de ruta 12, camino a San Carlos, 11-IV-1974, Krapovickas 24869 (CTES). Depto. San Cosme, ruta 6, 4,5 km. S de ruta 12, en canada, 23-II-1983, Carnevali 6025 (CTES). Depto. Santo Tome, Laguna la Luna, Galarza, en embalsado, VII1995, Schinini 6596 (CTES); Garruchos, costa del Rio Uruguay, 12-IV-1974, Krapovickas 25091 (CTES); Estancia Timbo, Arroyo Ciriaco y ruta 40, 27-II-1983, Schinini 23463 (CTES). Depto. San Roque, ruta 123, 15 km. W de 9 de Julio, 17-V-1983, Norrmann & Quarin 90 (CTES). Formosa. Depto. Bermejo, Puerto Bermejo, 2-III-1901, Kermes 634 (CTES). Depto. Pilcomayo, estero Isla Leona, ruta 86, 22-III-1979, Piccinini & Petetin 3 674 (CTES). Depto. San Pedro, ruta 20 y Arroyo Piray Guazu, 21-III-1997, Tressens 5704 (CTES). Depto. Monte Carlo, Monte Carlo, 22-V-1951, Montes 15388 (SI, BAA). Misiones. Depto. Capital, Posadas, 11-VI-1912, Ekman 549, 550 (CORD). Depto. San Pedro, 21-III-1997, Tressens 5704 (CTES). Depto. El Dorado, ruta provincial 17, Pozo Azul, 27-V-2002, Keller 1832 (CTES).

[FIGURE 4 OMITTED]

BRAZIL. Amazonas. Estrada Manaus, Porto Velho, Castanho Tupana, 7-VII-1972, Silva 184 (CTES). Minas Gerais. Ouro Preto, 22-I-1984, Schinini & Ferrucci 24590 (CTES). Parana. Region of villaje of Pratati, Sandy cerrado, 11-II1974, Anderson, W. 10784 (CTES); Piraquara, sine data, Dombrowski 10505 (CTES). Rio Grande do Sul. Igrejinha, estrada Taquara, Gramado, 7-IV-1971, Valls 11486 (CTES); Ijui, km. 346 da BR 285, 24-VII-1973, Valls 2682 (CTES); Torres, colonia Sao Pedro, 28-III-1970, Valls 1102 (CTES).

PARAGUAY. Alto Parana. Estancia Santa Elena, 5 km. N de Hernandarias, III-1995, Schinini & Caballero 27414 (CTES). Asuncion. Jardin Botanico, en terrenos modificados, 17-III1973, Schinini 6230 (CTES). Canindeyu. Jejuimi, 26-III-1996, Jimenez & Marin 71 (CTES); Lagunita, pastizal, 26-III-1996, Jimenez & Marin 43 (CTES). Central. Ipacarai, en camino a Patino, 27-II-1985, Mereles 226 (CTES); ruta 2 y Arroyo Mboiy, 2-III-1975, Schinini 10945 (CTES). Cordillera. Cordillera de Altos, Cerro Tobati, 9-III-1984, Schinini 24050 (CTES). Misiones. Santiago, Estancia La Soledad, 21-IV1961, Pedersen 5941 (CTES). Paraguari. Pirayu, en esteros, II-1983, Mereles 234 (CTES). Presidente Hayes. Ruta Trans, Chaco, km. 120, 25-IV-1989, Mereles 3019 (CTES); Estancia Maroma, 90 km. E de Pozo Colorado, 23-III 1995, Mereles 5931 (CTES).

Andropogon glaziovii Hack.

BRAZIL. Goias. 70 km. SE de Jatai, 12-IV1988, Valls 11712 (CTES); 39 km. SW de Gacu, 12-IV-1988, Valls 11720 (CTES). Mato Grosso do Sul. 5 km W de Ribas ao Rio Pardo, 14-IV 1988, Valls 11765 (CTES); Campo Grande, Norrmann 311 (CTES).

PARAGUAY. Amambay. Parque Nacional Cerro Cora, ruta 5, 18-IV-1995, Norrmann 163 (CTES). Concepcion. Ruta 5, 32 km noreste de Concepcion, 20-IV-1995, Norrmann 196, a, b, c, d (CTES). Misiones. 2 km E de San Juan Bautista por ruta 1, 21-IV-1995, Norrmann 217, a, b, c, d (CTES); 2,1 km E de San Juan Bautista por ruta 1, 16-IV-2009, Nagahama 87, 88, 89, i, ii, iii, iv (CTES). San Pedro. Ayo. Ipane y ruta 3, 20-IV-1995, Norrmann 203, a, b, c, d, e (CTES).

Andropogon x velutinus Norrmann & Nagahama (= A. bicornis x A. glaziovii)

PARAGUAY. Concepcion. 38 km E de Concepcion por ruta 5, 20-IV-1995, Norrmann 199, a, b, c, d, e (CTES). Misiones. 2 km E de San Juan Bautista por ruta 1, 21-IV-1995, Norrmann 218, 219, 222 a, b, c, d, e (CTES).

BRAZIL. Sao Paulo. Auriflama, SP 310, km 570, 27-XII-1984, Campbell 4704 (SP); Pereira Barreto, 31-XII-1984, Campbell 4705 (SP); 27-XII-1984, Campbell 4706 (SP).

Andropogon x catarinensis Norrmann & Nagahama, nothosp. nov. (= A. arenarius x A. bicornis). TYPE: Brazil, Estado de Santa Catarina, Itapiruba, 22-II-2008, N. Nagahama & G. A. Norrmann 49 (holotype CORD!; isotype CTES). Fig. 5.

[FIGURE 5 OMITTED]

Plants perennial, cespitose, culms 91-115 cm tall, nodes 9-18, glabrous. Leaf sheaths shorter and/or longer than the internodes, glabrous; blades 10-60 x 0.2-0.5 cm, base straight, linear, conduplicate or flat, glabrous on both surfaces or scabrous-pubescent on adaxial surface, apex acute or subobtuse; ligule 1-1.4 mm long, membranous ciliate. Inflorescences dense, 90.2-114.7 cm long, sub-congested, sub-corymbose, highly branched, composed of both terminal and axillary inflorescence units, these units 2.8-4.8 cm long, with 2-3 (-4) racemes, equal or subequal in length, partially enclosed by the spatheole, with intense hairiness; peduncle of the inflorescence unit 3.1-7.2 cm long; spatheoles 4.3-8 cm long. Pedicels and rachis internodes 2.1-3 mm long, both with hairs 8-11 mm long. Sessile spikelets perfect, 2.1-3.4 mm, awned, callus hairy. Lower glume 2-3.4 x 0.6-0.8 mm, slightly concave, lanceolate, chartaceous, glabrous on the margins, 2-3 nerved, acute apex; upper glume (2.1-) 3-4 x 0.7-0.9 mm, sub-chartaceous, ciliate on the upper half of the margins, 3-nerved, the lateral nerves tenuous, acute apex. Lower lemma 1.8-2.9 x 0.4-0.6 mm, bicarenate, hyaline or hyaline vinaceous, ciliate on the upper half of the margins, 0-2-nerved; palea absent; upper lemma 1-1.8 x 0.2-0.4 mm, lanceolate, hyaline or hyaline vinaceous, glabrous on the margins, 0-1-nerved, briefly bifid apex, awned, awn 1.6-4.5 mm long; palea 0.4-1 x 0.2-0.4 mm, hyaline, glabrous, 0-nerved, truncate or irregularly dentate apex. Lodicules 2, 0.5 mm long, glabrous. Stamens 3, anthers 0.8 mm long. Cariopsis not developed or undeveloped 0.7-1.6 x 0.2-0.5 mm. Pedicellate spikelets usually reduced, 1.3-2.4 x 0.05 mm long, lanceolate.

Distribution and habitat. One of the parental species, A. bicornis, lives in disturbed areas from Argentina to south EEUU. Therefore, the area occupied by A. x catarinensis is closely linked to the more restricted distribution limits of the other parental species, A. arenarius, occurring along the coastal dunes of southern Brazil (Santa Catarina, Sao Paulo, and Rio Grande do Sul) and Uruguay. Such geographical restriction is likely probably related to the sterility of the A. x catarinensis individuals, being found only in the sympatric areas of the parental species, where the F1 is formed.

Observations. Andropogon x catarinensis is a sterile alohexaploid (2n = 6x = 60).

Representative examined material

Andropogon bicornis L.

Refer to the examined material of Andropogon x velutinus.

Andropogon arenarius Hack.

BRAZIL. Rio Grande do Sul. Osorio, praia Atlantida, 02-II-1974, Valls 1468 (CTES); Osorio, em campo de dunas moveis, 10-IX-1972, Valls 2146 (CTES); Torres, beira da Praia, proximo ao Morro do Farol, 28-III-1970, Valls 1116 (CTES); Capao da Canoa, III-1992, Norrmann 104 (CTES, BAA). Santa Catarina. Itapiruba, 22-II-2008, Nagahama & Norrmann 29, 30, 31, 32, 23, i, ii, iii, iv, v (CORD); 02-I-1994, Norrmann 139 (CTES); Laguna, en dunas, 02-I-1994, Norrmann 224 (CTES).

Andropogon x catarinensis Norrmann & Nagahama (= A. arenarius x A. bicornis)

BRAZIL. Santa Catarina. Itapiruba, 22-II 2008, Nagahama & Norrmann 48, 49, 50, 58, 67, i, ii, iii, iv (CORD); Norrmann 331, 332 (CTES).

Key to the new named hybrids of Andropogon lateralis complex in this study
1. Inflorescences scarcely branched, main axis with 7-15
internodes and 4-9 branches. First branch on the
main axis of synflorescence 12.4-22 cm long, with 2-4
internodes and 1-5 branches. Second branch on the main
axis of synflorescence 8.1-13.6 cm long, with 2-3
internodes                                    A. arenarius

1. Inflorescences profusely branched, main axis with
15-28 internodes and 14-71 branches. First branch on
the main axis of synflorescence 22.3-61.2 cm long, with
5-11 internodes and 9-49 branches. Second branch on
the main axis of synflorescence 18-47.9 cm long, with
4-10 internodes                                          2

2(1). Articulate rachis internodes 2.2-3 mm long. Sessile
spikelet 0.3-0.4 mm lat. Pedicel less than 0.1 mm lat.,
with hairs 5-10 mm long                                  3

2. Length of articulated rachis internodes 1.4-2.1 mm
long. Sessile spikelet 0.4-0.7 mm lat. Pedicel 0.15-0.3
mm lat., with hairs 2.2-5 mm long                         4

3(2). Synflorescence 90.2-114.7 cm long. Second
branch on the main axis of synflorescence with 4-6
internodes. Hairs on articulate rachis internodes 9-12
mm long. Pedicel 2.4-3 mm long. Upper lemma of the
sessile spikelet awned, awn 1.1-4.8 mm long
                                         A. x catarinensis

3. Synflorescence 122.4-180 cm long. Second branch on
the main axis of synflorescence with 6-10 internodes.
Hairs on articulate rachis internodes 7-8.6 mm long.
Pedicel 3-4.5 mm long. Upper lemma of the sessile
spikelet awnless                               A. bicornis

4(2). Main axis of synflorescence with 37-71 branches.
First branch on the main axis of synflorescence with 3449
branches. Second branch on the main axis of synflorescence
with 8-10 internodes. Articulate rachis internodes
1.8-2.2 mm long., with hairs 4.9-6 mm long. Pedicel
2.5-3 x 0.1-0.2 mm, with hairs 4.5-5.1 mm long.
Pedicellate spikelet 1-2.3 x 0.1-0.2 mm     A. x velutinus

4. Main axis of synflorescence with 19-36 branches.
First branch on the main axis of synflorescence with 1032
branches. Second branch on the main axis of synflorescence
with 4-6 internodes. Articulate rachis internodes
1.4-1.8 mm long., with hairs 2.7-3.4 mm long.
Pedicel 1.5-2.5 x 0.2-0.3 mm, with hairs 2.2-3.1 mm
long. Pedicellate spikelet 2.5-4.1 x 0.2-0.7 mm
                                              A. glaziovii


Original recibido el 2 de abril de 2012, aceptado el 2 de junio de 2012.

ACKNOWLEDGEMENTS

We are grateful to Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET, PIP 112-200801-01557) and Secretaria de Ciencia y Tecnologia de la Universidad Nacional de Cordoba (SECyT-UNC), which supported this research as part of the Ph.D. dissertation of the first author. We thank the curators of CORD and CTES for specimen loans.

BIBLIOGRAPHY

Campbell, C. S. 1983. Systematics of the Andropogon virginicus complex (Gramineae). Journal of the Arnold Arboretum 64: 171-254.

Campbell, C. S. & P. Windisch. 1986. Chromosome numbers and their taxonomic implications for eight brazilian Andropogons (Poaceae). Brittonia 38: 411-414.

Cronquist, A. 1981. An integrated system of classification of flowering plants. New York: Columbia University Press.

McCune, B. & M. J. Mefford. 1999. Multivariate analysis of ecological data, version 4.25. Gleneden Beach: MjM Software.

Michener, C. D. & R. R. Sokal. 1957. A quantitative approach to a problem in classification. Evolution 11: 130-162.

Nagahama, N. 2012. Relaciones filogeneticas en el complejo Andropogon lateralis (Sect. Leptopogon, Andropogoneae, Poaceae). Doctoral Thesis. Universidad Nacional de Cordoba.

Norrmann, G. A. 2009. Natural hybridization in the Andropogon lateralis complex (Andropogoneae, Poaceae) and its impact on taxonomic literature. Botanical Journal of the Linnean Society 159: 136-154.

Zanin, A. 2001. Revisao de Andropogon L. (Poaceae--Panicoideae--Andropogoneae) no Brasil. Doctoral Thesis, Universidade de Sao Paulo.

Nicolas Nagahama (1), Ana M. Anton (1), Maria I. Hidalgo (2) & Guillermo A. Norrmann (2)

(1) Instituto Multidisciplinario de Biologia Vegetal (1MB1V)--CONICET, Casilla de Correo 495, 5000 Cordoba, Argentina; nagahama@imbiv.unc.edu.ar (author for correspondence).

(2) Facultad de Ciencias Agrarias, Instituto de Botanica del Nordeste, Universidad Nacional del Nordeste-CONICET, Av. Sargento Cabral 2131, Casilla de Correo 209, 3400 Corrientes, Argentina.
Table 1. Morphological characters analyzed.

Pedicel length

Pedicellate spikelet length

Sessile spikelet length

Length of hairs on pedicel

Awn length

Pedicellate spikelet width

Sessile spikelet width

Length of articulated rachis internodes

Length of hairs on articulated rachis internodes

Pedicel width

Synflorescence length

Number of internodes of the main axis of synflorescence

Number of branches on the main axis of synflorescence

Length of first branch on the main axis of synflorescence

Number of internodes of the first branch

Number of branches on the first branch

Length of second branch on the main axis of synflorescence

Number of internodes of the second branch
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Author:Nagahama, Nicolas; Anton, Ana M.; Hidalgo, Maria I.; Norrmann, Guillermo A.
Publication:Darwiniana
Date:Jul 1, 2012
Words:4015
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