Perennial from a thick, tuberous root, but grown as an annual; lvs ovate, petioled; invol cal-like, of 5 united bracts, deeply 5-lobed, 1-fld, 6-8 mm at anthesis; cal cor- like, showy, opening in late afternoon, white, yellow, red, purple, or variegated, funnelform, with long, slender tube 2-3 cm, the limb 2-3.5 cm wide; 2n=58. Native of tropical Amer., widely cult., and occasionally escaping in our range.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.