Isolona madagascariensis Engl.

Tree up to 8 m tall; d.b.h. to 10 cm; young branches drying black, glabrous; old branches dark brown, striate, glabrous. Petiole 5-6(-8), 1.5-2 mm in diameter, glabrous, leaf lamina inserted on side, very faintly grooved adaxially. Leaf lamina 13-22 cm long, 5-8 cm wide, length:width ratio: 2.5-2.7, elliptic (obovate), coriaceous, glabrous, base acute to narrowly cuneate, apex acuminate, acumen 1-2.5 cm; midrib glabrous on both sides; secondary veins 9-13, uniformally curved upwards, glabrous on both sides. Rhipidium 1, on leafy branches. Flowering pedicels 4-5 mm long, 1-1.5 mm in diameter, glabrous. Lower bracts 2-4, 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, base truncate, apex rounded, glabrous, falling in fruit; margins with short straight hairs. Corolla white-yellow when immature to light red at anthesis; tube 4-5 mm long, 4-5 mm wide, lobe:tube ratio: 1.7-2.7, clearly urceolate around receptacle, glabrous; lobes 7-12 mm long, 3-4 mm wide, length:width ratio: 2.3-3.6, narrowly ovate to narrowly oblong, narrowed at base, apex attenuate, glabrous, coriaceous; margins glabrous. Receptacle ca. 4 mm in diameter. Stamens 1-1.2 mm long, connective shield ca. 0.2 mm long, glabrous, those of innermost whorl elongated and pressing against ovary wall. Ovary ca. 2 mm long, 1.7 mm wide; stigma ca. 3 mm in diameter, glabrous. Fruiting pedicels ca. 5 mm long, 3-4 mm in diameter, glabrous. Fruits ca. 5 cm long, 4.5-5 cm wide, length:width ratio ca. 1, globose, apex rounded, finely ribbed, glabrous, green; pericarp 7-9 mm thick. Seeds 12-16 mm long, 7-9 mm in diameter, transversely ellipsoid; testa smooth, light brown; raphe not thickened; hilum 6-7 mm long, 2-4 mm wide, elliptical to oblong.