Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Genus Description - Perianth regular, tubular, shortly 6-lobed; stamens included, inserted on the perianth-tube; anthers introrse, oblong-linear or sagittate; ovary ovoid to globose, 3-locular; ovules numerous in each locule; style slender, shorter than the perianth; stigma capitate, obscurely lobed; fr a dark blue or black, several-seeded berry; herbs from a knotty rhizome with conspicuous large scars marking the position of previous stems; stem erect or arching, bearing in the upper part numerous alternate lvs in 2 ranks and short, axillary, 1–15- fld peduncles with pendulous, white to greenish or yellow fls. 50, N. Temp.