Carcuera, Costilla, Tigre, Canalua Tree, to 30 m or more, usually 75-100 cm dbh; trunk with conspicuous, deep, irregular, longitudinal invaginations in age; bark soft, minutely fissured, the sap becoming reddish-brown in time, with a foul odor at least in younger parts. Leaves alternate, imparipinnate, to 25 cm long; petiole, rachis, petiolule, and underside of blade puberulent; leaflets 10-20, oblong, rounded to emarginate at apex, obtuse to rounded at base, 2.5-7.5 cm long, l-3 cm wide, glabrous above. Inflorescences lax racemes from upper axils; pedicels 8-12 mm long, bracteate near apex; bracts oblong, ca 2 mm long, persistent; calyx ca 4 mm long, turbinate, sparsely appressed-pubescent, the carinal tooth acute, equaling lateral teeth, the vexillar teeth +/- united; corolla yellow-orange; petals clawed; standard reniform, ca 1.8 cm long; keel petals fused only near apex; stamens ca 1 cm long, 2 stamens free, the others in clusters of 4 each; stigma about as long as anthers. Samaras obliquely oblong, to 13 cm long and 3 cm wide, on stipes ca 2 cm long; seminiferous area distal. Croat 5411. Common. Flowers synchronously every two years from April to June (sometimes as early as March), apparently initiated by the beginning of the rainy season. The fruits may be full size by June but mature over a long period, ripening by December or January. Leaves are replaced in the dry season before the time of flowering. A few individuals are out of phase (R. Foster, pers. comm.).