| Scientific Name | Common Name | Habitat | Description | Toxic Principle |
| Aconitum spp. | monkshood | moist meadows and open woods | palmately lobed herb, blue-purple flowers, hooded sepal. | alkaloids, including aconitine. |
| Actea arguta Nutt.x T.&G. | baneberry | woods, moist ground | ternate herb, red or white berries in racemes. | essential oils found in the fruit. |
| Amaranthus retroflexus L. | pigweed | dry, disturbed areas | annual weed, leaves alternate with prominent veins, spikes w/bracts. | nitrates and oxalates |
| Ambrosia tomentosa Nutt. | silver leaf poverty weed | dry plains and hills | Perennial, bipinnatifid leaves, tomentose beneath, strigose above, fruit burlike | nitrates |
| Apocynum canabinum L. | indian hemp, dogbane | open places, along sreams or roadsides | Perennial herb, woody stems, 5 ft. tall with milky juice and seeds with a tuft of hair. | resins and glycosides; cymarin |
| Asclepias spp. | milkweed | Dry plains and foothills | Narrow leaves, greenish-yellow flowers with horns forming umbels, 3 or more leaves at the node. | galatoxins |
| Aster falcatus Lindl. | white fall aster | Plains, hills and streambanks | Perennial, leaves 1-3 cm long, densely hairy, inflorescence head with white rays flowers and pappus bristles. | secondary seleniom absorber |
| Astragalus spp. | milk vetch | Dry alkaline meadows at middle elevations | Perennial, leaves odd-pinnate flowers in dense racemes, purple or pinkish-white. Fruit a pod | selenium and alkaloids |
| Avena fatua L. | oatgrass | Cultivated areas or roadsides | Annual with flat, narrow leaf blades; infloresence an open panicle; twisted awns. | nitrate, photosensitation |
| Castilleja spp. | paintbrush | Mountains and plains | Herbaceous, leaves alternate and sessile irregular flowers in bracted spikes, two lipped corolla. | selenium |
| Centaurea solstitialis L. | yellow star thistle | Waste areas and roadsides | Annual weed; leaves covered with a cottony hair and deeply lobed at base; yellow disc flowers ; bracts tipped with yellow spines. | toxic metabolite |
| Cercocarpus montanus Raf. | mountain mohogany | Dry slopes and mesas | Shrub or tree like, leaves simple oval to linear, flowers small w/yellowish sepals and no petals. | cyanogenic glycoside |
| Cicuta douglasii (DC.) Coult & Rose | water, poison hemlock | Moist ground or standing water | Stout erect glabrous plant;1-3 times pinnate; roots tuberous. | cicutoxin |
| Convulvulus sp. | bindweed | Disturbed areas, dry hills and plains | Perennial trailing herbs with alternate leaves; flowers solitary, white, pink, blue. | Nitrates purgative principles |
| Corydalis aurea Willd. | golden smoke | Disturbed areas, roadsides | Low growing, fleshy taproot, 2-3 times pinnate leaves; yellow racemes, flowers spurred and fragrant. | aporphine, berberine, protoberberine and protopine |
| Datura stramonium L.
D. wrightii Regel |
jimsonweed | Waste areas | Shrubby-like, nearly glabrous, leaves ovate with acute lobes, large white flowers; fruit is a spiny capsule | atropine, hyoscyamine hyocine, nitrate |
| Delphinium spp. | larkspur | Low plains or high mountain meadows | Perennial herb; leaves palmately divided; flowers in terminal racemes, irregular, spurred | alkaloids, delphinine |
| Dugaldia hoopesii Rydb. | sneeze weed | Mountain valleys | Erect perennial stems unbranched except near inflorescence, leaves entire; orange ray and discs | dugaldin |
| Euphorbia esula L. | leafy spurge | Waste areas, roadsides | Perennial, erect several rayed umbels whorled leaves at the base of the umbels | unknown, found in the juice |
| Grindelia spp. | gumweed | praries plains and roadsides | Perennial herb with solitary heads. Resinous bracts, yellow flowers | selenium poisoning |
| Gutierrezia sarothrae (Pursh) Britt. & Rusby | broom snake weed | plains and hills | Perennial, woody at the base, yellow heads, linear leaves | saponins and selenium |
| Helianthus annuus L. | sunflower | fields and waste places | Annual herb, leaves rough and alternate, flowers yellow and reddish-purple | nitrates |
| Hymenoxys richardsonii (Hook.) | Colorado rubberweed | open ranges | Perennial herb with tufts around the stems, yellow heads | unknown |
| Hypercium perforatum L. | St. Johnswort | roadsides and waste areas | Perennial herb with woody stems at the base, branches opposite, inflorescence is a yellow cyme. | hypericin |
| Iris missouriensis Nutt. | blue flag | moist meadows | Perennial herb, horizintal root stalk, yellowish-white flowers | irisin |
| Linium lewisii Pursh. | wild blue flax | open areas | Slender stem and leaves light blue flower | linamarin |
| Lobelia siphilitica L. | great lobelia | along water courses | Perennial herb with alternate leaves, inflorescence is a blue raceme | alkaloids, including lobeline |
| Lupinus argentus Pursh. | silvery lupine | dry hills, mountains, valleys and plains | Low perennial herb with palmately compound leaves, inflorescence is a bluish raceme | alkaloids and turatogens |
| Malva parviflora L. | mallow | waste places, gardens | Annual herbs with reniform lobed leaves, flowers pink | nitrates |
| Nicotiana attenuata Torr. ex S. Wots. | wild tobacco | dry sandy streambeds | Herbaceous annual or perennial, leaves lanceolate, white flowers in racemes | nicotine and anabasine |
| Oxalis spp. | wood sorrel | moist woods, waste places | Herbaceous annuals or perennials, decumbent, 3-foliate, yellow cymes | potassium and sodium oxylates |
| Oxytropic sericea Nutt. ex Torr. & Gray. | white loco weed | well drained slopes in lower elevations | Perennial herb, leaves odd pinnately compound, covered in silvery hairs, scapose, white raceme | locoine |
| Panicum spp | panic grass | dry woodlands | A bunch grass, scaly rhizomes with culms, open widespreading panicle | unknown |
| Penstemon spp. | beard -tongue | mountains and plains | Perennial herb, opposite leaves, inflorescence is a panicle | selenium |
| Physalis longifolia Nutt. | ground cherry | valleys and plains | Perennial herb, solitary yellow and brown flower, lanceolate leaves | unknown |
| Polygonum spp. | smartweed | waste ground, moist areas | Annual or peennial, swollen nodes, racemes | nitrates |
| Portulaca oleracea L. | purslane | waste places | Annual succulent, prostrate stems which are pinkish, yellow solitary flowers | oxalates |
| Prosopsis spp. | mesquite | dry ranges and washes | Deciduous shrub or tree, leaves bipinnate, inflorescence is a catkin-like spike | unknown |
| Prunus virginiana (A. Nels.) Sarg. | western chokecherry | thickets and slopes | Shrub or tree with grey bark, leaves sharply serrate and thick, inflorescence is a raceme and fruit dark purple | HCN |
| Quercus spp. | oak | dry hills and along streams | Small trees and shrubs, simple toothed or lobed leaves, catkins and flowers in clusters or solitary, fruit is and acorn | gallotanin |
| Ranunculus scleratus | blister buttercup | along lakes and streams | Herb with fibrous roots, basal leaves reniform, upper leaves are sessile, flowers yellow | ranunculin |
| Rheum rhaponticum L. | rhubarb | moist areas | Herbs with fleshy roots and 1-2 meters long stems, flowers greenish white | oxalates found in the leaves |
| Ricinus communis | castor bean | gardens | Annual herb with large, palmately lobed, serrate leaves, fruit a spiny capsule | ricin |
| Rumex crispus L. | dock | acid soil, roadsides | Perennial herb, no axillary branches, oblong leaves, inflorescence is a compound raceme, seeds brown | oxalate |
| Salsola kali | russian thistle | disturbed areas | Branched annual herb, leaves are spine tipped, small flowers with two bractlets | nitrates and oxaltes |
| Saponaria officinalis | cow cockle | waste areas and crop lands | Erect herb with jointed stems, simple leaves, flowers white or pink, in cymose clusters | saponin |
| Sarcobatus vermiculatus (Hook.) Torr. | greasewood | alkaline soils | Deciduous shrub, spiney and woody, unisexual flowers, in catkins or solitary | soluble oxalates |
| Senecio spp. | groundsel | varies among species | Perennial herbs with yellow flowers | alkaloids |
Reference: Walter, Richard. 1999. Poisonous Plants Lecture Notes.