Acer rubrum L.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Species Description - Tree to 35 m; winter buds with 6–10 imbricate scales; young twigs red; lvs sharply but shallowly lobed, coarsely double-serrate, or with a few minor lobes, acute or short-acuminate, ± pubescent beneath when young; functionally dioecious; fls generally red, unisexual, short-pedicellate in fascicles from a cluster of lateral buds, opening much before the lvs; sep oblong, distinct, 1 mm, the pet a little narrower and longer, oblong-linear; ovary glabrous; mericarps mostly 2–4 cm; 2n=78, 91, 104, perhaps other nos. Swamps, alluvial soils and moist uplands, often as a successional tree; Nf. to se. Man., s. to Fla. and e. Tex., but missing from Io., most of Ill., and n. Mo. (Rufacer r.; R. drummondii; Acer carolinianum; A. stenocarpum) Morphologically, cytologically and ecologically variable, but indivisible.