Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Genus Description - Sep 6; pet none; stamens 12; pistils 3, narrowed to the summit and there radially dilated into a lobed stigma; fr ellipsoid, flattened on one side; stone deeply excavated on one side, its margin somewhat incurved and erose; woody twiners. Monospecific.