A genus of poisonous, perennial herbs (or, rarely, low shrubs) that have rhizomes, palmate, lobed leaves some of which are radical, the stem leaves occurring in a whorl of 3 some way below the flowers, and solitary flowers (or occasionally 2 or 3 flowers together). They have a perianth of 1 whorl, which is petal-like, and many free stamens and carpels. The fruit is a head of unplumed achenes. There are about 120 species, almost cosmopolitan and especially found in northern temperate regions.
Subjects: Plant Sciences and Forestry.