Shrubs or small trees. Bark grey, smooth and lenticellate when young, dark and much cracked on older stems; branches stiff. Leaves opposite, 8-12 cm long (on shrubs sometimes only 2 cm long), midrib winged; leaflets 5-11, up to 4 cm long and 2.5 cm broad, ovate-lanceolate or ovate-oblong, crenate, glabrous or slightly hairy on midrib beneath, sessile or subsessile. Flowers in dense heads, appearing before or with the young leaves on shoots of the previous year; bracts wooly, brown. Calyx lacking in male flowers, small and persistent in bisexual flowers. Corolla lacking. Filaments short, anthers oblong. Samarae spatulate, often emarginate, 3-4 cm long, in dense fascicles, rachis hardly 5 mm long.