Plants polygamous, with reduced fls in separate staminate and fertile infls appearing with the lvs from spur-branches; hypanthium short-campanulate; perianth regular, pubescent, of 2 similar yellowish-green series of 3-5 members each, the pet a little larger than the sep; stamens mostly 5-8; anthers versatile, longitudinally dehiscent; pods large, flat, oval to elongate, woody and scarcely (or very tardily) dehiscent; trees with branched thorns (some cultivars unarmed), usually with 2 kinds of lvs, those of the long shoots bipinnate, those of the spurs mostly only once pinnate. 14, widespread.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.