Flora of Barro Colorado Island

Myroxylon balsamum

(L.) Harms var. pereirae (Royle) Harms, Notizbl. Königl. Bot. Gart. Berlin 5:95.1908

Balsam, Balsam of Peru

Tree, to 35 (40) m tall and ca 1 m dbh; trunk straight; branches ascending; outer bark smooth, bearing abundant lenticels; heartwood reddish-brown; sapwood pale, the freshly cut bark emitting a pungent, obnoxious odor. Leaves alternate, generally imparipinnate, fragrant when crushed; petioles 1-4 cm long; rachis and petiolules   pu­bescent, terete; rachis 5-15 cm long; leaflets 5-10, alter­nate on rachis, lanceolate to elliptic, acute to acuminate, obtuse at base, 3-11 cm long, 1.8-4 cm wide. Racemes axillary, to 20 cm long, closely cinereous-tomentose; pedicels 1-1.5 cm long; flowers oblique on pedicel; calyx campanulate, 3.5-4.5 (6) mm long, with obvious, fine ribs, the lobes ca 1.5 mm long; standard orbicular, ca 9 mm diam, cordate basally, the claw ca 1 mm long; wings elliptic to narrowly spatulate, ca 1 cm long, ca 4 mm wide, their claws 2 mm long, the keel subelliptic, ca 8.5 mm long and 3 mm wide, its claw ca 1.5 mm long; ovary sparsely villous, borne on stipe 2 mm long; style subulate. Samaras narrowly obovate, to 11 cm long, glabrous, on stipes to 1 cm long; wing to 8 cm long, l-2 cm wide, the seminiferous area turgid, at the apex of the fruit, obliquely oblong, 2-3 cm wide, ca 1 cm thick, extending as a low, longitudinal ridge into the pedicel; appearance of fruit much like that of Platypodium elegans. Ebinger 215.

Apparently rare; collected once on the island. Flowers from January to June. Fruits from September to March. Southern Mexico to the Amazon basin of Brazil and Peru; planted as a street tree in Ceylon and in tropical botanical gardens. In Panama, known only from tropical moist forest in the Canal Zone, Panama, and Darien. Characteristic of tropical moist forest in Panama (Tosi, 1971). Holdridge (1970) reported it for low and medium elevations in moist and wet areas with a dry season.