Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Genus Description - Monoecious or dioecious; perianth deeply 3-lobed, subglobose; anthers 3, sessile on the base of the perianth-lobes, opening transversely; ovary ovoid; fr a subglobose to ovoid, sessile berry; small shrubs, parasitic on trees, with well developed (in most spp.), opposite, coriaceous lvs and small fls in short, axillary spikes. 200, New World.