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Toxic plants in Prairie Gardens.

Plants are the original inventors of chemical warfare. During millions of years of evolution, they have had to cope with greedy, inconsiderate herbivores that robbed them of their resources and the fruits of their labours (literally). While plants capitalized on some of these interactions to their own benefit, for example to use animals for pollination and seed dispersal, in many other cases they had to devise ways of discouraging marauders and limiting damage if they were to survive. Although physical defenses (spines, thick cell walls, heavy coverings) provided some relief, the battleground moved into the chemical arena very early. Even the most primitive leafless vascular plants such as Psilotum are not helpless prey, but are loaded with nasty-tasting purgative phlobaphenes.

Compared to animals, plants are biochemically advanced. Besides producing all of the molecules required for primary metabolism (respiration, photosynthesis, and protein, lipid and nucleic acid synthesis and breakdown), plants have developed an incredible array of convoluted metabolic pathways to produce thousands of secondary compounds that play a role in defence, storage and other functions (some common examples are listed in Table 1, next page). These substances may taste or smell bad, or better still, many provide a permanent solution by being toxic. Some, such as precocenes, which prevent juvenile insects from moulting into reproductive adults, mimic animal hormones and thus control pest populations. Other chemicals deter disease invaders (antimicrobial and antifungal agents), confer plant immunity (phytoalexins), discourage other plants from encroaching on the plant's personal space (allelopathic compounds), or are simply indigestible and, therefore, waste the herbivore's time and energy (e.g., inulin instead of starch in dahlia tubers). Plants have experimented with molecular structures in the most creative and ingenious ways, even devising ways to incorporate environmental toxins such as selenium and fluorine into organic compounds that are toxic to animals but not to the plants themselves.

To deal with different kinds of herbivores and feeding preferences, many plants have diversified their chemical arsenals by producing more than one type of toxin at the same time. The target varies. Compounds can be nerve, heart or liver poisons, may disable kidneys, may disrupt blood clotting or cause anemia, interfere with iodine metabolism, cause gastrointestinal rebellion, block key respiratory enzymes, act as carcinogens (e.g., furanocoumarins in bergamot oil, which has been banned from lotions by the European Union since 1995), or cause photosensitization when the animal is exposed to sunlight. In other cases, simple contact with the plant may produce severe allergic reactions and skin lesions. Every animal metabolic pathway has a plant compound that affects it. Many of these substances, accordingly, provide us with useful drugs and natural pest control products.

In our own role as herbivores, it is therefore important for us to be aware of potentially harmful plants, especially in our gardens. Toxins are almost impossible to avoid in our foods, and our bodies are able to handle small amounts of substances such as cyanide compounds in almonds or oxalic acid in spinach without visible ill-effect. However, injudicious consumption of large quantities can very quickly lead to toxicity. The threshold is a very fine line and depends on the individuals and their age, state of health, and sometimes gender, genetic make-up of both consumer and plant, and many other factors which are still unknown.

We also need to be aware that many medicinal plants used in herbal therapy may be toxic if: used in unsuitable dosages; stored or prepared incorrectly; the inappropriate plant part (or inappropriate stage of growth) is used; the plant has been cultivated under questionable conditions (e.g., heavy metals, nitrates, pesticides); or if it is used in combinations with certain other ingredients (drugs or food) which may interact. Of particular concern are herbal weight-loss preparations (e.g., Lamiaceae, some Euphorbiaceae), which may cause permanent liver damage even when immediate effects might not be apparent. Whether you are dosing yourself or you are using purchased, ready-made preparations, you must be cautious because in numerous cases, plants have been incorrectly identified or adulterated by suppliers. It is best to stay away from more exotic ethnic imports.

For some species, only certain parts may be toxic, as for example potatoes, tomatoes or asparagus. Or just a part of a plant may be toxic: in rhubarb, only the green part of the leaf is toxic due to soluble oxalates but the stalk contains much lower concentrations. Other plants may be toxic only at certain stages of their life cycle--for example, lettuce becomes toxic once it has bolted and started to flower, causing an illness known as lettuce opium poisoning (which has nothing to do with true opium, so don't get any ideas). The bitter compounds that develop at this stage give us some warning that it should not be eaten. Yet others may become toxic if grown under certain conditions. Good examples are spinach and chard, which should never be grown in soil richly fertilized with nitrogen, as they may accumulate enough toxic nitrates in the leaves to cause an illness called methemoglobinemia (in people) or nitrate toxicosis (in livestock). Some canned spinach has had to be recalled for this reason. Other reported nitrate accumulators include celery, beet, turnip, broccoli, sweet potato, lettuce, radish, cucumber, squash, sunflower and even corn. So it is wise never to overdo the chemical fertilizer or manure. Nitrate absorption is aggravated even more in plants that have been exposed to herbicides like 2,4-D or MCPA. Thus nitrate toxicosis in cattle can become a big problem in pastures that have been sprayed, where there is already a high amount of nitrogen in the soil.

Some plants may produce toxins depending on the genetic strain and environmental conditions. Prussic acid (cyanide) in lima beans may reach 0.3% in some strains from South America. Although Canada prohibits importation of lima beans with more than 0.02% prussic acid, small quantities of heritage seeds may still find their way into Canadian gardens undetected. Mediterranean peoples are especially susceptible to illness from fava bean consumption (a type of anemia called favism) because of a particular X-linked human gene.

Beet leaves may contain more oxalates than rhubarb leaves in some conditions (levels of 12% by weight have been reported), and it is impossible to predict how much is present in the plants from your particular garden at any given time, as toxin levels depend on variety of beet, age of the leaves, soil and light conditions, stress and so on. Irreversible silent liver and kidney damage are the rewards of frequent consumption, and may lead to fatal uremic shock (many traditional recipes still include beet leaves). Similarly, oxalic acid in sorrel (Rumex crispus) has resulted in human death after ingestion of 500 grams of leaves prepared as sorrel soup, and this plant is frequently responsible for death of sheep both here on the prairies and in Europe.

Many other plants that were used indiscriminately by our grandmothers (grandfathers hardly ever seemed to cook) have now been redlined as more information comes to light. Raw kidney bean seeds contain toxic lectins which fortunately are destroyed on cooking. These proteins cause pathological changes in the intestinal lining and inflammation of heart muscle; numerous cases of poisoning have been recorded in children and adults from batches of undercooked beans. Similarly, there are many recipes for green tomatoes: these should be consumed with caution and in moderation as they contain alkaloids with neurological and gastrointestinal effects designed to deter mammals from eating the fruit before the seeds are ready to be dispersed.

Plants that are poisonous to people are also often poisonous to livestock and other animals, but not necessarily vice versa. NEVER assume that because you see an animal or bird eating something, that it is safe for humans to eat. Squirrels, for example, often die from plant or mushroom poisoning in the wild. Contrary to popular myth, they DON'T know any better than we do. As any gardener knows, deer are often seen to eat toxic species (such as delphinium), even when food isn't especially scarce. Birds can safely eat many kinds of berries that are toxic for mammals, such as cotoneaster and yew. Bees can collect nectar from poisonous plants like rhododendron and azalea, which, although harmless for bees, yields poisonous honey for us. Sometimes however, plants which may seem harmless for us, such as onions, may prove fatal for dogs, cats and livestock, causing a type of lethal anemia. Similarly limonene in citrus oils is repellent and toxic to cats and many other animals; hence its use in animal deterrent products.

A good rule is don't eat or taste any plant with which you are unfamiliar. Also, supervise children in the garden and train them from an early age never to put leaves, berries or even flowers into their mouths. For instance, children have been poisoned by sucking nectar out of angel's trumpet flowers (Datura). Wash your hands after handling poisonous plants, or better still, wear gloves, and don't rub your eyes. Don't feed the discards from your garden to cattle, horses or pigs. It is amazing how many animals continue to die needlessly from being allowed to eat tomato and potato stalks, leafy beet tops, bolted lettuce and rhubarb leaves tossed "over the garden fence."

Don't use flowers and leaves from plants of which you are not sure to decorate food. Some lavishly illustrated cookbooks show food decked with poisonous flowers--while this makes for a prettier picture, it is not so pretty if you try to copy the picture and picture yourself afterwards in the emergency ward. Flowers which are generally thought to be edible include rose, nasturtium, giant hyssop (Agastache faeniculum), common hyssop (Hyssopus officinalis), honeysuckle (Lonicera caprifolium), bergamot, fennel, basil, chive, summer savory, marjoram, hop, various mint species, pot marigold, pinks (Dianthus), hollyhock, stocks (Matthiola), angelica, squash, dandelion, sunflower petals. Note that allergic reactions and unpredictable interactions with other food ingredients may affect certain individuals, therefore always use in moderation. Persons with diabetes, or liver or kidney ailments are especially susceptible to adverse reactions. Crystallized violets, a Victorian favorite, are not commonly seen now, owing to their tendency to cause diarrhea and cramps.

Table 2 (next page) lists some of the toxic plants that are commonly found in prairie gardens. For many plants, some parts have been shown to be poisonous, but there may be insufficient data regarding the other parts. So if a species part is already listed, don't assume that the other parts are safe, unless they have been proven. This is how these data are collected--from somebody's unfortunate experience. You probably don't want to become another testimonial in this hall of fame!

Suggested Reading:

Blackwell, W.H. 1990. Poisonous and Medicinal Plants. Prentice Hall, Englewood Cliffs, NJ.

Bruneton, J. 1999. Toxic Plants Dangerous to Humans and Animals. Lavoisier Publishing, Paris.

Emboden, W. 1979. Narcotic Plants. Collier Books, New York, NY.

Hole, L. 2000. Herbs & Edible Flowers. Hole's, St. Albert, AB.

Kingsbury, J.M. 1965. Deadly Harvest. Holt, Rinehart and Winston, New York, NY.

Leggatt, J. 1987. Cooking with Flowers. Fawcett Columbine, New York, NY.

Newdick, J. & M. Lawrence. 1991. Flowers as Food. Crescent Books, New York, NY.

Ott, J. 1976. Hallucinogenic Plants of North America. Wingbow Press, Berkeley, CA.

Stephens, H.A. 1984. Poisonous Plants of the Central United States. University of Kansas Press, Lawrence, KS.

Tampion, J. 1977. Dangerous Plants. David & Charles Publishers, Vancouver, BC.

Warning: The following articles deal with more toxic plants. Many are highly poisonous and are not recommended for gardens used by children or pets. Always wash your hands thoroughly after handling any toxic plant, and it is recommended that gloves be worn at all times. Ingesting such plants can be deadly. Ingestion is not recommended.

Dr. Eva Pip is a Full Professor at the University of Winnipeg. She lives in the Cloverleaf area in Eastern Manitoba. Eva has taught courses in plant anatomy, physiology and taxonomy for over 25 years.
Table 1: Some Examples of Common Plant Secondary Com wounds

Compound         Where Found

Alkaloids        In many flowering plant families,
                 >10,000 identified so far

Unusual amines   In many flowering plant families,
                 often flowers

Cyanogenic       At least 2650 species in 130
glycosides       families, often seeds and young
                 leaves

Cardiac          Some Apocynaceae, Asclepiadaceae,
glycosides       Scrophulariaceae, Brassicaceae,
                 Crassulaceae and others

Glucosinolates   Brassicaceae and other families in
                 order Ca aridales

Coumarins        A iaceae, Rutaceae and others

Unusual          Convolvulaceae, Sterculiaceae, castor
fatty acids      bean (ricinoleic acid)

Phenols          Universal

Monoterpenes     In >50 families with essential oils,
                 localized in specialized cells and
                 ducts

Diterpenes       Many latex and resin producing
                 secies

Limonoids        Turaceae, Meliaceae, Simaroubaceae

Cucurbitacins    Cucurbitaceae and some others

Sesquiterpene    Asteraceae, Lauraceae and others
lactones

Tannins          Widespread, especially in woody
                 species
Saponins         Sporadic

Polyacetylenes   Asteraceae, Umbelliferae

Unusual          Leguminosae
dipeptides

Unusual          Leguminosae and orb ers
proteins

Selenium         Asteraceae, Leguminosae,
compounds        Cheno odiaceae, Scro hulariaceae

Fluorine         Leguminosae, Rubiaceae,
compounds        Dichapetalaceae

Compound         Qualities

Alkaloids        Bitter and/or toxic, many
                 interfere with animal
                 neurotransmitters

Unusual amines   Unpleasant taste, some
                 hallucinoraenic

Cyanogenic       Cyanide released when
glycosides       compounds react with digestive
                 enzymes

Cardiac          Increase strength of cardiac
glycosides       muscle contractions, decrease
                 heart rate

Glucosinolates   Unpleasant taste

Coumarins        Cause hemorrhtye

Unusual          Interfere with lipid metabolism
fatty acids

Phenols          Antimicrobial

Monoterpenes     Volatile with strong odour, may
                 intoxicate

Diterpenes       Astringent taste, some toxic

Limonoids        Unpleasant taste

Cucurbitacins    Unpleasant taste, some toxic

Sesquiterpene    Allergens, neurolo?ical toxins
lactones

Tannins          Inhibit digestion by binding to
                 proteins; some toxic
Saponins         Detergents; stimulate intestinal
                 contractions and hemolyze
                 blood cells
Polyacetylenes   Some toxic

Unusual          Lathyrogens cause paralysis,
dipeptides       premature in (lath rism)

Unusual          Allergens, hematemesis,
proteins         fainting, blood clots

Selenium         Appetite loss, reproductive
compounds        problems

Fluorine         Toxic respiratory enzyme
compounds        inhibitors

Table 2: A Partial List of Common Toxic Prairie Garden Plants

This list does not include houseplants, native species or fungi.
Where only genera are listed, all species should be considered
suspect until more data prove otherwise.
See end of table for notes.

Name                    Common Name

Aconitum *              Monkshood

Acorus calamus          Sweet Flag

Aerculus                Buckeye

Agrostemma              Ornamental Corn Cockle

Allium giganteum        Giant or Tibetan Onion

Amaranthus              Amaranth

Amaryllis               Amaryllis

Anchusa                 Summer Forget-Me-Not

Anemone                 Anemone

Antirrhinum             Snapdragon

Aquilegia               Columbine *

Arisaema triphyllum     Jack in the Pulpit

Artemisia *             Silver Artemisia, Wormwood

Asdepias                Monarch Butterfly Milkweed

Asparagus               Asparagus

Aster                   Aster

Azalea                  Azalea

Baptisia                False Indigo

Begonia                 Begonia

Beta vulgaris ***       Beets

Borago officinalis **   Borage

Browallia               Browallia, Blue 'Violet'

Brugmansia *            Brugmansia, Trumpet Flower

Caladium                Caladium, Angel Wins

Caltha palustris        Marsh Marigold

Clematis                Clematis

Colocasia               Elephant's Ear

Convallaria majalis     Lily of the Valley

Convolvulus             Morning Glory

Corydalis               Fumatory

Cotoneaster             Cotoneaster

Craetegus               Hawthorn

Cyclamen *              Cyclamen

Cynoglossum             Chinese Forget-Me-Not

Datura *                Angel's Trumpet

Daucus                  Carrot, Queen Anne's Lace

Delphinium              Larkspur (annual + perennial)

Dicentra *              Bleeding Heart

Dictamnus *             Gas Plant, Fraxinella

Digitalis *             Foxglove

Echinops                Globe Thistle

Escholtzia              California Poppy

Eupatorium              Joe Pye Weed

Festuca arundinacea     Tall Fescue

Fritillaria             Crown Imperial, Fritillary

Galanthus               Snowdrops

Gladiolus               Gladiolus

Gloriosa superba *      Gloriosa Lily Vine

Hedera helix            English Ivy

Helenium                Helen's Daisy, Sneezeweed

Heliotropium *          Heliotrope

Hyacinthus              Hyacinth

Hydrangea               Hydrangea

Hypericume perforatum   St. John's Wort

Impatiens               Impatiens

Ipomoea                 Morning Glory

Iris                    Iris

Lactuca sativa          Lettuce

Lathyrus                Sweet Pea
                        (annual +
                        perennial)

Ligularia               Groundsel

Lilium                  Garden Lilies

Linum                   Flax
                        (scarlet +
                        perennial)

Lobelia                 Lobelia

Lupinus *               Lupine

Lycopersicon            Tomato
esculentum

Malus *                 Apple

Menispermum             Moonseed
canadense

Mirabilis jalapa        Four O'Clock

Monarda                 Bergamot

Myosotis                Forget-Me-Not

Nicotiana *             Flowering Tobacco

Narcissus               Daffodils, Narcissus

Nierembergia            Nierember is

Nymphaea, Nuphar        Water Lily

Ornithogallum           Star of Bethlehem

Paeonia                 Peony
lactiflora

Papaver *               Poppies

Parthenocissus          Virginia Creeper
virginianus

Penstemon               Beard's tongue

Petunia                 Petunia

Phaseolus lunatus       Broad or Lima Bean,
                        Fava Bean

Phaseolur vulgaris      Kidney Bean

Philadelphut *          Mock Orange

Polygonatum             Solomon's Seal

Portulaca               Portulaca

Prunus *                Plum, Cherry, Apricot

Pteridium aquilinum     Bracken Fern

Ranunculus              Buttercup

Rheum *                 Rhubarb

Ricinus *               Castor Bean

Rumex *                 Sorrel, Yellow Dock

Salvia reflexa          Ornamental
                        (annual) Salvia

Sambucus                Elderberry

Sanguinaria             Bloodroot
canadensis

Saponaria               Soapwort

Scilla *                Squill

Solanum *               Potato, Nightshade

Solidago                Goldenrod

Sorbus                  Mountain Ash

Symphytum officinale    Comfrey

Tanacetum               Tansy

Tulipa                  Tulip

Vinca                   Periwinkle

Zantedetchia            Angel Wings,
                        Caladium

Scientific
Name                    Poisonous parts

Aconitum *              All parts

Acorus calamus          Root

Aerculus                All pparts

Agrostemma              Leaves

Allium giganteum        All parts

Amaranthus              All parts

Amaryllis               Bulb

Anchusa                 All parts

Anemone                 All parts

Antirrhinum             Leaves

Aquilegia               All parts

Arisaema triphyllum     All parts

Artemisia *             All parts

Asdepias                All parts

Asparagus               Berries, mature leaves

Aster                   All parts

Azalea                  All parts

Baptisia                All parts

Begonia                 All Paris

Beta vulgaris ***       Leaves only

Borago officinalis **   Leaves, flowers

Browallia               All parts

Brugmansia *            All parts

Caladium                All parts

Caltha palustris        Leaves

Clematis                Leaves

Colocasia               All parts

Convallaria majalis     All parts

Convolvulus             Seeds

Corydalis               All parts

Cotoneaster             Berries

Craetegus               Fruits

Cyclamen *              Roots

Cynoglossum             All parts

Datura *                All parts

Daucus                  Leaves

Delphinium              All parts, young foliagemost toxic

Dicentra *              All parts

Dictamnus *             All parts

Digitalis *             All parts

Echinops                Leaves

Escholtzia              Seeds

Eupatorium              All parts

Festuca arundinacea     Leaves

Fritillaria             All parts

Galanthus               Bulbs

Gladiolus               Corms (bulbs)

Gloriosa superba *      All parts

Hedera helix            Leaves

Helenium                All parts

Heliotropium *          All parts

Hyacinthus              All parts

Hydrangea               Leaves

Hypericume perforatum   Leaves

Impatiens               Leaves

Ipomoea                 Seeds

Iris                    All parts

Lactuca sativa          Leaves of bolted plants

Lathyrus                Seeds

Ligularia               All parts

Lilium                  All parts

Linum                   Leaves

Lobelia                 All parts

Lupinus *               All parts

Lycopersicon            All green parts
esculentum

Malus *                 Bark, leaves, seeds

Menispermum             Leaves, fruits
canadense

Mirabilis jalapa        Roots, seeds

Monarda                 Leaves

Myosotis                All parts

Nicotiana *             All green parts

Narcissus               All parts

Nierembergia            All parts

Nymphaea, Nuphar        All parts

Ornithogallum           All parts

Paeonia                 Seeds
lactiflora

Papaver *               Leaves, pods

Parthenocissus          Berries and seeds
virginianus

Penstemon               All parts

Petunia                 All parts

Phaseolus lunatus       All parts (If
                        grown in
                        nitrogen
                        fertilized
                        conditions)

Phaseolur vulgaris      RAW seeds only

Philadelphut *          Seeds

Polygonatum             Berries

Portulaca               Leaves

Prunus *                Leaves, bark,
                        seeds inside pits

Pteridium aquilinum     All parts

Ranunculus              All parts

Rheum *                 All green parts

Ricinus *               All parts

Rumex *                 Leaves

Salvia reflexa          Leaves

Sambucus                Leaves, bark

Sanguinaria             Roots
canadensis

Saponaria               Seeds

Scilla *                All parts

Solanum *               All green parts, berries

Solidago                Leaves

Sorbus                  Berries

Symphytum officinale    All parts

Tanacetum               All parts

Tulipa                  All parts

Vinca                   All parts

Zantedetchia            All parts

Scientific
Name                    Toxic Agent(s)

Aconitum *              Diterpenoid alkaloids (aconite)

Acorus calamus          Asarone

Aerculus                Coumarin, Glycosides

Agrostemma              Saponins

Allium giganteum        Alkaloids

Amaranthus              Nitrates

Amaryllis               Alkaloids

Anchusa                 Alkaloids

Anemone                 Protoanemonin, glycosides

Antirrhinum             Purgativeve (alkaloid?)

Aquilegia               Alkaloids, thu'one

Arisaema triphyllum     Oxalic acid

Artemisia *             Alkaloids, sesquiterp enes

Asdepias                Alkaloids, resinoids, cardiac glycosides

Asparagus               Unidentified toxin

Aster                   Selenium compounds

Azalea                  Resinoids

Baptisia                Quinolizidine alkaloids

Begonia                 Unidentified toxin

Beta vulgaris ***       Oxalic acid, nitrates

Borago officinalis **   Alkaloids (lycopsamine,
                        thesinine, amabiline)

Browallia               Alkaloids

Brugmansia *            Tropane alkaloids

Caladium                Oxalates

Caltha palustris        Protoanemonin

Clematis                Protoanemonin

Colocasia               Oxalic acid

Convallaria majalis     Cardiac glycosides
                        (convallarin,convallatoxin)

Convolvulus             LSD-like hallucinogens

Corydalis               Isoquinoline alkaloids

Cotoneaster             Cyanogenic glycosides

Craetegus               Cyanogenic glycosides

Cyclamen *              Unidentified toxin

Cynoglossum             Alkaloids

Datura *                Tropane alkaloids, nitrates

Daucus                  Nitrates

Delphinium              Diterpenoid alkaloids

Dicentra *              Alkaloids (protopine)

Dictamnus *             Alkaloids, furans, limonoids

Digitalis *             Cardiac glycosides

Echinops                Quinoline alkaloids

Escholtzia              Alkaloids

Eupatorium              Nitrates, pyrrolizidine
                        alkaloids, toxic alcohol
                        (tremetol)
Festuca arundinacea     Alkaloids

Fritillaria             Alkaloids

Galanthus               Alkaloids

Gladiolus               Emetic substances

Gloriosa superba *      Alkaloids

Hedera helix            Sa onins

Helenium                Glycosides (dugaldin)

Heliotropium *          Pyrrolizidine alkaloids
                        (lasiocarpine, heliotrine)

Hyacinthus              Unidentified toxin

Hydrangea               Cyano enic glycosides

Hypericume perforatum   Resinoids (hypericin)

Impatiens               Unidentified toxin

Ipomoea                 LSD-like hallucinogens

Iris                    Alkaloids, resinoids

Lactuca sativa          Toxic latex compounds

Lathyrus                Varies with species

Ligularia               Pyrrolizidine alkaloids

Lilium                  Emetic substances

Linum                   Cyanogenic glycosides

Lobelia                 Alkaloids (emetic)

Lupinus *               Quinolizidine alkaloids(ana yrine)

Lycopersicon            Steroidal alkaloids(solanine)
esculentum

Malus *                 Cyano enic glycosides

Menispermum             Alkaloids
canadense

Mirabilis jalapa        Stomach irritant

Monarda                 Furanocoumarins

Myosotis                Alkaloids

Nicotiana *             Alkaloids (nicotine)

Narcissus               Alkaloids

Nierembergia            Alkaloids

Nymphaea, Nuphar        Alkaloids

Ornithogallum           Alkaloids

Paeonia                 Resveratrol
lactiflora

Papaver *               Isoquinoline alkaloids(morphine)

Parthenocissus          Unidentified toxin
virginianus

Penstemon               Selenium compounds

Petunia                 Alkaloids

Phaseolus lunatus       Cyanogenic
                        glycosides
                        (linamarin)
                        (causes favism)

Phaseolur vulgaris      Hemagglutinins,
                        toxiclectins

Philadelphut *          Unidentified toxin

Polygonatum             Anthra uinones

Portulaca               Oxalic acid

Prunus *                Cyanogenic glycosides

Pteridium aquilinum     Thiaminase

Ranunculus              Promanemonin, glycosides

Rheum *                 Oxalic acid

Ricinus *               Ricinoleic acid, ricin

Rumex *                 Oxalic acid

Salvia reflexa          Nitrates

Sambucus                Alkaloids

Sanguinaria             Alkaloids
canadensis

Saponaria               Sa onins

Scilla *                Cardiac glycosides

Solanum *               Steroidal alkaloids
                        (solanine), nitrates

Solidago                Nitrates, (resinoids
                        at flowering time)

Sorbus                  Unidentified toxin

Symphytum officinale    Alkaloids (echimidine)

Tanacetum               Tanacetin

Tulipa                  Tulipalin

Vinca                   Alkaloids

Zantedetchia            Oxalic acid

All parts = leaves, roots, flowers, fruits and seeds

* = human fatalities have been reported. There are probably
fatalities for some of the other species, but
many jurisdictions do not require such deaths to be reported.

** In Germany in 1991 borage was banned from use
in medicine and commercial products.

*** Hundreds of livestock deaths reported from beet tops.
COPYRIGHT 2006 This material is for informational use. Views are not those of the editorial committee. Reference to commercial products is made with no discrimination intended or endorsement by The Prairie Garden.
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 2006 Gale, Cengage Learning. All rights reserved.

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Author:Pip, Eva
Publication:Prairie Garden
Geographic Code:1USA
Date:Jan 1, 2006
Words:3358
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