Young persistent branchlets distinguished from deciduous branchlets by shorter segments and differences in shape or size of leaves; furrows deep and closed, concealing stomates. Infructescences pedunculate, pubescent at least when immature; bracts thin in exposed portion, not vertically expanded; bracteoles ± protruding from surface of infructescence, never greatly thickened, always lacking dorsal protuberance. Samaras pale yellow-brown or grayish, dull, glabrous. x = 9. Hybrids are frequent in cultivation; in the flora, hybrids are known between all combinations of the three species.