(Seem.) Hemsl., Biol. Centr.-Amen. Bot. 2:495. 1882
Tree, 15-40 (50) m tall, to 1.5 (2) m dbh, usually lacking prominent buttresses, glabrous except for minute, simple or stellate trichomes in vein axils of leaflets below and on a few flower parts; outer bark thick, deeply fissured vertically, the plates between fissures broken into scales, flaky and shaggy on older trees; wood very hard, heavy; branchlets subtetragonal; pseudostipules and interpetiolar glands lacking. Leaves palmately 5- or 7-foliolate, deciduous; petioles 7-10 (23) cm long; petiolules 2-4.5 cm long; leaflets ovate to elliptic, acuminate, acute to broadly rounded at base, minutely glandular-dotted, entire, the terminal leaflet largest, 9-30 cm long, 3.5-15.5 cm wide. Flowers precocious, the panicles dense, terminal; calyx campanulate, 1-1.5 cm long, usually shallowly 5-lobed, sparsely stellate-pubescent; corolla yellow, 6-11 cm long, almost as wide, glabrous outside, softly pubescent on nectar guides inside, the tube brownish, the lobes 4-4.5 cm long, obovate; stamens held against glabrous side of tube, the longer pair 1.5-2.5 cm long, the shorter 12-17 mm long; filaments arched, each pair of anthers facing each other, the thecae divaricate, 2-3 mm long; pistil 2.4-3.3 cm long; ovary linear, 3-5 mm long, glabrous to lepidote. Capsules cylindrical, terete with conspicuous irregular ridges and tubercles, 30-50 (61) cm long, 1.5-2.5 (2.9) cm diam, glandular-lepidote; seeds 9-11 mm long, 3.5-4 cm wide, the wings hyaline-membranaceous, sharply demarcated from body of seed. Croat 5388, 7940.
Frequent in the forest. Flowers almost exclusively in one or two brief bursts during the dry season (January to May), but with occasional asynchronous individuals flowering during the rainy season. The fruits mature mostly near the end of the dry season, but some seeds fall in the early rainy season. Leaves fall during the dry season.
The species can be recognized by having leaves often with seven leaflets and stellate trichomes in the lower vein axils (Gentry, 1973b).
Mexico to Colombia. In Panama, known from tropical moist and tropical wet forests in the Canal Zone, Colon, and Darien, from premontane moist forest in Panama, and from premontane wet forest in Chiriqui.
See Fig. 499.