Stems viny, climbing or trailing (plants scarcely viny perennials in var. dissecta ). Leaf blade 1-ternate (or terminal leaflet sometimes ternate in var. dissecta ), ± firm but not succulent; leaflets lance-ovate to triangular or suborbiculate, lobed or unlobed, margins entire or toothed. Flowers: sepals violet-blue, reddish violet, or white, lanceolate to ovate or elliptic-oblong.
Subglabrous trailer or climber, to 2 m; lfls 3, long-stalked, ovate, entire to crenate or lobed; fls solitary, mostly axillary; sep reddish-violet, lance- ovate, 3-5 cm, softly villous; outer filaments progressively broader and with smaller anthers; the outermost often completely sterile and prominently veined; achenes villous, in a dense, globular head; mature styles flexuous, plumose, 3-5 cm; 2n=16. Rocky woods; e. Que. to Man., s. to N.J., Del., O., nw. Ill., and ne. Io., and in the mts. to N.C. May, June. (C. verticillaris; Atragene americana)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.