Flora of Barro Colorado Island

Pithecellobium macradenium

Pitt., Contr. U.S. Natl. Herb. 20:465.1922

Tree, to 30 (40) m tall, to 1 m dbh; young branchlets with brownish short pubescence, becoming glabrous and sometimes lenticellate in age. Leaves bipinnate with 3-5 pairs of pinnae, the axes minutely pubescent; petioles 4-7 cm long; stipules acicular, caducous; rachis 8-16 cm long, bearing a large cupular gland to 1 cm long between pairs of basal pinnae and a smaller gland at node of suc­cessive pair; pinnular rachis to 15 cm long, with small glands at nodes; leaflets in 7-12 pairs per pinna, asymmet­rical, ovate to oblong, obtuse to rounded at apex, usually obtuse at base, 2-5 cm long, l-2 cm wide, minutely  appressed-puberulent with longer trichomes on midrib. Flowers in condensed umbels or short spikes; peduncles    5-12 cm long, ferruginous-tomentose; floral rachis ca 5 mm long; pedicels 1-2.5 mm long; flowers pale green, 9-12 mm long excluding stamens, with minute, brown, appressed trichomes outside; calyx 5-6 mm long, the lobes irregular, ca 2 mm long, sometimes ± cleft on one side; corolla usually 5 (6)-lobed ca one-third its length, fused to the staminal tube near base; stamens many, ca 3 cm long, the staminal tube nearly as long as corolla. Legumes linear, short- stipitate, curved into a nearly com­plete circle ca 6 cm diam, to 12 cm long and 2-2.5 cm wide, very thick at seminiferous areas, the valves splitting apart and twisting to display seeds; seeds flattened, ovoid, ca 8 mm long, on alternate segments of the valve. Croat 5205.

Uncommon; known only from a few places along the north shore and in the forest on the north side of the island. Flowers principally from February to May, with the fruits maturing from April to September, chiefly in the rainy season.

Costa Rica and Panama. In Panama, reported by Hol­dridge (1970) from wet regions at low elevations; col­lected only from tropical moist forest on the Atlantic slope in the Canal Zone. Reported from tropical wet forest in Costa Rica (Holdridge et al., 1971).

See Figs. 271 and 272.