Tree 5–23(–30) m. high; crown flat or not; bark smooth, grey, or sometimes brownish and rough. Young branchlets densely, sometimes sparsely, and shortly brown-pubescent (grey to golden in var. tephrocalyx) , later glabrescent. Leaves: rhachis shortly and densely to sparsely pubescent; pinnae 2–7 pairs; leaflets (of the 2 distal pairs of pinnae) 6–21 (–23) pairs (sometimes as few as 5 pairs on lower pinnae), variable in shape and size, obliquely oblong, or rhombic to falcate-oblong, acute to rounded and mucronate at the apex, which is turned towards the pinna-apex, with diagonal midrib, 7–21(–30) mm. long, 3.5–8.5(–16) mm. wide, ± appressed-pubescent beneath and often whitish when dry, glabrescent above. Flowers white or pale yellow, pedicellate; pedicels 2–6 mm. long, densely and shortly brown- (grey in var. tephrocalyx) pubescent or sometimes puberulous, as are the calyces and corollas. Calyx 1.5–2.5 mm. long, not slit unilaterally. Corolla 4–7.5 mm. long. Staminal tube not or scarcely exserted beyond corolla; filaments about 0.7–1.2 cm. long. Pod oblong, 18–34 cm. long, (2–)2.8–5.9 cm. wide, puberulous (sometimes sparsely so), not glossy, venose, brown. Seeds 9–11 mm. long and 6.5–8 mm. wide, flattened.
