Stems erect, glabrous and glaucous when young, 1 to 3 feet high from a thickened, perennial rootstock; the base of the stem with two or three large, sheathing bracts, near the top of the stem a single, large, triternate, nearly sessile leaf and usually a similar but smaller leaf near the base of the inflorescence. Leaflets thin, oval, oblong or obovate, 1 to 3 inches long when mature, visually only partly developed at flowering time, three to five-lobed at the apex. Flowers several in a loose terminal panicle, greenish purple, one-quarter to one-half of an inch broad; sepals six, oblong; petals six, smaller, cucullate and opposite the sepals; stamens six. Each flower contains a single pistil with two ovules, which ripens into a globose, blue, glaucous, berrylike fruit, about one-third of an inch in diameter. As the seed grows it ruptures the thin, transparent pericarp before maturity.
Memoir 15 N. Y. State Museum
Blue Cohosh - Caulophyllum thalictroides