Description by L. R. Landrum, unpublished, incomplete
Psidium oblongatum:
Tree or shrub up to 7(-15) m high, essentially glabrous, except for puberulent disk, inner surface of calyx, ovary locules within and sometimes petals; hairs reddish brown to whitish, up to ca. 0.3 mm long; young twigs glabrous, smooth reddish brown to grayish, the older twig bark becoming only slightly rough.LEAVES elliptic to lanceolate, 5-17.5 cm long, 1.7-5.9 cm wide, 2.5-3.6 times as long as wide; apex acute to acuminate; base acute to attenuate; petiole channeled, 2-8 mm long, 1-2 mm wide; venation brochidodromous, the midvein impressed above, prominent below, the lateral veins 10-18 pairs, moderately prominent, leaving midvein at an angle of greater than 45 degrees, the marginal vein arching between the laterals, about equaling laterals in prominence, the tertiary veins usually weak, appearing to arise from the laterals, branching dendritically towards midvein; blades subcoriaceous, drying reddsih brown, to gray-green.FLOWER BUDS pyriform, 5-10 mm long, the hypanthium* obconic, 2-4 mm long, the distal portion of bud subglobose 3-6 mm long; indumentum pattern of buds with all external surfaces exceptbracteoles glabrous, the bracteoles puberulent, the calyx puberulent within, the disk puberulent, the petals puberulent or not, sometimes with cilate margins; peduncles 1-flowered, 1-11 mm long, ca. 0.8 mm wide, borne in axils of leaves or bracts, or at leafless nodes, often clustered on bracteate shoots; bracteoles ovate to narrowly triangular, 1-1.5 mm long, caducous before anthesis. CALYX closed in bud (sometimes with an apiculate tip) or with an apical pore up to 3 mm wide, tearing irregularly at anthesis; petals presumed to be suborbicular,ca. 8 mm long; hypanthium obconic to campanulate, 2-3 mm long; disk 5-6 mm across; stamens 180-300, ca. 5 mm long; anthers 0.5-0.6 mm long, with a terminal gland and 3-6 small glands below; style ca. 5 mm long; ovary 3-4-locular, the locules puberulent within; ovules 25-51 per locule, biseriate on each lamella of a peltate placenta.FRUIT globose to pyriform, 2.5-3 cm long; seeds ca. 22 in fruit seen, reniform to subovoid, up to ca. 7 mm long.