Poisonous Plants
Top, left to right: star-of-Bethlehem, belladonna , poison ivy , poison oak , bottom: yew , oleander, wisteria , and poison hemlock . Poisonous Plants, plants containing substances that, taken into the body of humans or animals in small or moderate amounts, provoke a harmful reaction resulting in illness or death. Possibly as many as one out of each 100 species of plants is poisonous, but not all have been recognized as such. Dangerous plants are widely distributed in woods (baneberry) and fields (star-of-Bethlehem), swamps (false hellebore) and dry ranges (scrub oak), roadsides (climbing bittersweet) and parks (kalmia), and may be wild (celandine) or cultivated (wisteria). Many ornamental plants, such as oleander, lily of the valley, and mistletoe, are poisonous. Botanists have no set rules to determine accurately whether any given plant is poisonous. Toxic species are scattered geographically, in habitat, and in botanical relationship. They contain more than 20 kinds of poisonous pri...