Isolona perrieri Diels

Tree up to 10-15 m high; d.b.h. to 20 cm; bark mottled light and dark grey with thin black lines; young branches drying black, glabrous; old branches grey, glabrous. Petioles 5-8 mm long, 1-1.2 mm in diameter, glabrous, leaf lamina inserted on side, faintly grooved adaxially. Leaf lamina 10-18 cm long, 3-4 cm wide, length:width ratio 3-4.2, narrowly elliptic, glabrous, green glossy, base narrowly cuneate to decurrent, apex acuminate, acumen 5-15 mm long; midrib glabrous on both sides; secondary veins 8-12 pairs, uniformally curving upwards, glabrous on both sides. Rhipidia 1-2, on leafy branches, sometimes on older leafless branches. Flowering pedicels (4-)10-15 mm long, ca. 0.5 mm in diameter, glabrous. Lower bracts 2-4, ca. 0.5 mm long, ca. 0.5 mm wide, glabrous. Upper bract absent. Sepals ca. 2 mm long, ca. 2 mm wide, length:width ratio ca. 1, very broadly ovate, glabrous, yellow, usually persistent in fruit; margins glabrous. Corolla green or light yellow when immature, bright yellow to purple red at anthesis; tube 2-6 mm long, 3-5 mm in diameter, lobe:tube ratio 2.5-5, glabrous; lobes (8-)11-20 mm long, 2-4 mm wide, length:width ratio 4-7, linear to very narrowly elliptic, coriaceous, spreading horizontally, sometimes curved and then spreading, glabrous. Receptacle ca. 4 mm in diameter. Stamens ca. 1.2 mm long; connective shield ca. 0.1 mm long, glabrous, those of innermost stamens extended or rarely slightly so over adjacent ovary wall. Ovary ca. 2 mm long, ca. 1.5 mm wide; stigma ca. 1.8 mm in diameter, glabrous, red at anthesis. Fruiting pedicels ca. 3.5 cm long, woody. Fruits 9-13 cm long, 5.5-7 cm in diameter, length:width ratio 1-1.5, globose to obconic, apex rounded to apiculate, apicule ca. 5-8 mm, striate, green, glabrous; pericarp ca. 5 mm thick. Seeds 22-25 mm long, 10-12 mm in diameter, ellipsoid, packed in white pulp; testa smooth, light brown; raphe not thickened, brown; hilum 7-8 mm long, 3-3.5 mm wide, elliptical.