Memoirs of The New York Botanical Garden
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of Vascular Plants of Northeastern United States and adjacent Canada
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
- Fleshy covering of the seed bright orange-red at maturity, globular- cupuliform, open at the end. 10, widespread, mainly N. Temp.