Guayabo de monte Tree, to 35 m tall; trunk to 90 cm dbh; buttresses many, to 1.5 m high, occasionally with many protruding knots; outer bark loose, falling away from trunk in large pieces; inner bark at first pale lemon-yellow, soon becoming tan; stems rufous-pubescent when young, soon glabrous and fissured. Leaves alternate; petioles 3-10 mm long; blades +/- narrowly elliptic, acuminate, acute and sometimes falcate and inequilateral at base, mostly 5-15 cm long, 3-6 cm wide, mostly membranous, glabrous, minutely and densely pellucid-punctate, arched along the midrib; reticulate veins prominent. Inflorescences terminal, to 15 cm long; flowers yellowish-green, sessile; upper receptacle cup-shaped, ca 2.5 mm long; calyx lobes triangular, reflexed, ca 1 mm long, pubescent outside, lanate inside; petals lacking; stamens 8, exserted, to 7 mm long. Fruits broadly 2-winged, with a single medial ridge on one side, to 2.5 cm long and 3.8 cm wide, emarginate at apex with the tissue sharply twisted to one side. Croat 13922. Uncommon, in the forest. Flowers mostly in the early dry season, especially in January. The fruits mature quickly and are dispersed mostly by the beginning of the rainy season. Leaves drop in June. Possibly more than one species exists. R. Foster (pers. comm.) has detected striking differences in fruits from different plants of this species. In one type the seeds are about half as long as broad, with the medial ridge straight. In the other type, the seed is 1.5 times as long as broad, with the medial groove twisted into a weak S from one end to the other. No intermediate forms have been seen and nothing is known of the significance of the differences. According to the label on Skutch 3990 (Costa Rica), the flowers are protogynous. The typical T. chiriquensis has a smooth white trunk. Allen (1956) reported this species as T. lucens Hoffm., but that species was published as T. lucens Hoffm. ex Mart. and is from Brazil.