Dioecious; epicalyx none; cal-lobes ovate or triangular, shorter than the tube; pet white; stamen-column bearing anthers at the summit in the staminate fls, in the pistillate fls reduced to a short sheath surrounding the ovary and bearing sessile anthers in a distal ring; carpels ca 10, 1-seeded, at maturity becoming rugose on the back and sides, irregularly dehiscent, beakless or obscurely apiculate; tall perennial herb. Monospecific.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.