Fls unisexual, basal in groups of 3, the central one staminate and long-pedicellate with a minute bract near the middle of the pedicel, the 2 lateral ones pistillate and sessile; staminate fls with 4 sep, 4 short, spreading cor-lobes, and 4 long-exsert stamens; pistillate fls with 3 or 4 sep and narrowly urceolate, 3-4-lobed cor; fr an achene, enclosed by the persistent cal; acaulescent herbs. 3, New World and Europe.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.