This is a distinctive genus of three species; one in temperate forests of eastern Asia, and our two. The bright glaucous blue “fruit” is more conspicuous and attractive than the flowers, and may remain on the plant through the winter; it is actually the naked fleshy seed; the ovary wall shriveling and pushed to the side as the seed bursts through it, enlarges, and ripens. The style may usually be found, even in mature plants, on aborted ovaries in which the seed has not enlarged. The foliage resembles that of Thalictrum; it is always completely glabrous and, especially when young, strongly purplish tinted.

1. Flowers usually purple or greenish-purple, the first opening with the leaves tightly condensed; style ca. 1-1.5 mm long.

C. giganteum

1. Flowers yellow, greenish, or yellow lightly tinged with purple, first opening after the leaves are largely expanded; style ca. 0.1-0.7 mm long.

C. thalictroides