Tree, to 20 (30) m tall; trunk to 30 (90) cm dbh, often widely buttressed; wood yellow or whitish, the sap copious, red; trichomes on younger parts and inflorescence axes minute, appressed-ferruginous, otherwise glabrous. Leaves alternate; petioles 2.5-11 cm long; petiolules 4-6 nun long; leaflets 5-9, oblong to ovate-oblong, acuminate, rounded to truncate at base, 3.5-17 cm long, 2.5-7.5 cm wide, the terminal leaflet largest. Panicles terminal or upper-axillary, to ca 25 cm long; calyces and pedicels reddish-brown; pedicels to 4 mm long; calyx ca 6 mm long, markedly toothed, glabrous except on the upper margin; standard obovate, ca 1 cm long, rounded at apex, yellow-orange, with a red, inverted V-shaped area in the middle, the lateral margins folding back along these lines; wings shorter than the standard, exceeding keel, the keel petals weakly connate on outer upper margins; stamens weakly connate, often free above the middle-, ovary glabrous or bearing a few trichomes on one edge. Fruits indehiscent, stipitate for ca 3 mm, suborbicular, +/- flattened; wing asymmetrical, not quite oblong on 1-seeded fruits, to ca 5 cm long on 2-seeded ones, dark brown or black when mature, glabrous; seminiferous area ca 1 cm thick, the margins thick and hard, distinctly veined, corky; seeds 1 or 2, to ca 3 cm long. Knight 1043. Rare. Flowers in central Panama from April to October, but mostly in June and July. The fruits mature from August to October (sometimes to December). Leaves fall in the early dry season. Although the Knight collection cited here is sterile, it is almost certainly this species. Knight reported it as common, but most of the specimens he had were P. rohili. Bangham 502, reported as this species in the Flora of Panama is really P. rohrii also. R. Foster (pers. comm.) has seen fruits of P. officinalis along the shore. The description given here is based on material from nearby areas of the Canal Zone. On the Atlantic slope from Belize to the mouth of the Amazon and on the Pacific slope from Panama to Ecuador; West Indies. In Panama, known from tropical moist forest in the Canal Zone, Bocas del Toro, Panama, and Darién and from premontane wet forest in Colon. Typical of tropical moist forest in Panama (Tosi, 197 1) and occasionally forming pure stands next to mangroves (Holdridge & Budowski, 1956).