Tall buttercup is a perennial weed characterized by erect stems and deeply lobed leaves. This species reproduces only by seeds. Tall buttercup produces a short, thick rootstalk with many fibrous, coarse, spreading roots. Young plants form a rosette. The first true leaves are hairy, round to heart-shaped in general outline, and shallowly lobed and toothed. Stems are erect, hairy, branched in the upper portion, and 1 to 3 1/2 feet tall. A single root crown generally produces several stems in a cluster. 1 inch wide flowers occur on long stalks in branched clusters at the tops of stems. The 5 to 7 petals are yellow or cream, and about 1/2 inch long. Directly below the petals are 5 hairy, green leaves. Tall buttercup contains a bitter, irritating oil called protoanemonin that is toxic to grazing livestock and other animals. The toxic oil is released when fresh leaves and stems are grazed, causing irritation and blistering of the skin and the lining of the mouth and digestive tract.
