'..thousands of PLANTS in the world are toxic, and thousands of separate toxins are present in these plants. ..Some common Plant foods are toxic, but the hazard is reduced through selection of edible parts or time of harvest, by genetic selection, or by processing.' [R. F. Keeler, 'Toxins in Plants', in The Safety of Foods, H.D.Graham Ed., AVI Publ. Co. Inc.,Westport, CO, 1982]

Some poisonous PLANTS:

     Aconite [Aconitum spp.], Alfalfa [Medicago sativa] , Alsike [Clover Trifolium], Alsike Clover [Datura spp.], Angel's Trumpet [Datura spp.], Amaryllis belladonna [Hippeastrus spp.], Arrowgrass [Triglochin maritima] , Baneberry [Actaea spp.], Belladonna [Atropa belladonna], Birdsfoot Trefoil [Lotus corniculatus] , Bittersweet [Celastrus scandens], Black Locust [Robinia pseudoacacia], Black nightshade [Solanum nigrum], Bleeding Heart [Dicentra spp.], Bloodroot [Sanguinaria canadensis], Blue cohosh [Caulophyllum thalictroides], Blue night shade [Solanum dulcamara], Bouncing Bet [Saponaria spp.], Bracken Fern [Pteridium aquilinium], Broad Beans [Vicia spp.], Buckeye [Aesculus spp.], Buckwheat [Fagoypyrum esculentum], Buffalo Bur [Solanum spp.], Buttercups [Ranunculus spp.], Caley Pea [Latyrus spp.], Castor Bean [Ricinus communis], Celandine [Chelidonium majus], Chinaberry [Melia azedarach], Christmasberry [Heteromeles arbutifolia], Christmas Rose [Helleborus niger], Cocklebur [Xanthium strumarium], Corn Cockle [Agrostemma githago], Corn Lily [Veratrum californicum], Cow Cockle [Saponaria spp.], Creeping Charlie [Glechoma spp.], Crown Vetch [Coronilla varia], Cherries, Cherry Black [Prunus spp.], Cherry Bitter [Prunus spp.], Cherry Choke [Prunus spp.], Cherry Pin [Prunus spp.], Coyotillo [Karwinskia humboldtiana], Daphne [Daphne spp.], Deadly Nightshade [Atropa belladonna], Death Camas [Zigadenus spp.], Delphiniums [Delphinium spp.], Devil's Trumpet [Datura spp.], Dock [Rumex spp.], Dogbane [Apocynum spp.], Doll's-eyes [Actaea spp.], Downy Thornapple [Datura], Drooping Leucothoe [Leucothoe axillaris], Dutchman's Breeches [Dicentra spp.], Elderberry [Sambucus canadensis], English ivy [Hedera helix], Fiddleneck [Amsinckia intermedia], Flax [Linum usitatissimum], Fool's parsley [Aethusa cynapium], Foxglove [Digitalis purpurea], Golden Chain/Laburnum [Laburnum anagyroides], Great lobelia [Lobelia spp.], Cardinal flower [Lobelia spp.], Indian tobacco [Lobelia spp.], Gill-over-the-Ground [Glechoma spp.], Groundsels or ragwort [Senecio spp.], Halogeton [Halogeton glomeratus], Henbane [Hhyoscyamus niger], Holly [Ilex spp.], Horsebrush [Tetradymia spp.], Horse Chestnut [Aesculus spp.], Horse Nettle [Solanum spp.], Horsetail [Equisetum arvense spp.], Irises [Iris spp.], Jack-in-the-Pulpit [Arisaema spp.], Japanese Pieris [Pieris japonica /+ spp.], Jerusalem cherry [Solanum pseudo-capsicum], Jessamine [Gelsemium sempervirens], Jimsonweed [Datura stramonium], Johnson Grass [Sorghum spp.], Klamath Weed [Hypericum perforatum], Lamb's Larkspurs [Delphinium spp.], Lily-of-the-Valley [Convallaria majalis], Locoweed [Aastragalus / Oxytropis spp.], Lupine [Lupinus spp.], Manchineel tree [Hippomane mancinella], Matrimony vine [Lycium halimifolium], Marijuana [Cannabis sativa], Marsh Marigold or Cowslip [Caltha palustris], Mayapple or Mandrake [Podophyllum peltatum], Mexican Poppy [Argemone mexicana], Milkweed [Asclepias spp.], Milo [Sorghum spp.], Monkey [Amanita spp.], Monkshood [Aconitum columbianum /+ spp.], Moonseed [Menispermum canadense], Mountain Fetterbush [Pieris japonica], Mountain laurel /sheep laurel [Kalmia spp.], Nightshade/Black Nightshade [Atropa belladonna], Oak Trees [Quercus spp.], Oleander [Nerium oleander], Onions [Allium spp.], Pigweed [Amaranthus spp.], Poison hemlock [Conium maculatum], Poison ivy [Toxicodendron radicans], Poison oak [Toxicodendron diversiloba],  Poison suckleya [Suckleya suckleiana], Poison Sumac toxicodendron vernix], Potato [Solanum spp.], Poinsettia [Euphorbia spp.], Pokeweed [Phytolacca americana], Ponderosa Pine [Pinus ponderosa], Poppies [Papaver spp.],  Purple Vetch [Vicia spp.], Poppy Prickly [Argemone mexicana], Psilostrophe [Psilostrophe tagetinae], Quarters [Chenopodium album], Ragworts [Senecio spp.], Red Clover [Trifolium spp.], Rhubarb [Rheum rhaponticum], Rosary Pea [Abrus precatorius], Saint John's Wort [Hypericum perforatum], Senecio [Senecio spp.], Sensitive Fern [Onoclea sensibis], Sierra Laurel [Leucothoe davisiae], Skunk Cabbage [Symplocarpus foetidus], Squirrel Corn [Dicentra spp.], Snow-on-the-Mountain [Euphorbia spp.], Sorghum [Sorghum spp.], Spider lily [Hymenocallis americana], Spring rabbitbrush [Tetradymia glabrata], Spurges [Euphorbia spp.], Star-of-Bethlehem [Ornithogalum umbellatum], Stinging Nettle [Urtica spp.], Sudan Grass [Sorghum spp.], Swamp lily  [Crinum asiaticum], Sweetclover Melilotus [Melilotus officinalis], Everlasting Pea [Latyrus spp.], Singletary Pea [Latyrus spp.],Tall Fescue [Festuca arundinacea], Tansy [Tanacetum vulgare], Tiger lily [Lilium tigrinum], Tobacco [Nicotiana spp.], Tung Tree [Aleurites fordii], Vetch [Vicia spp.], Water Hemlock or Cowbane [Cicuta spp.], Western sneezeweed [Helenium hoopesii], White Snakeroot [Eupatorium urticaefolium/rugosum], Wisteria [Wisteria spp.], Wolfsbane [Aconitum spp.], Yellow Star [Centaurea solstitialis], Yew [Taxus spp.].

[References: http://museum.gov.ns.ca/poison/ppleaf.htm
 http://res.agr.ca/brd/poisonpl/ppcommo2.html
html://aggie-horticulture.tamu.edu/PLANTanswers/publications/poison/poison.html
http://www.ces.ncsu.edu/depts/hort/consumer/poison/indcoa_e.htm ]