Isolona heinsenii Engl. & Diels

Tree or shrub to 6(-12) m tall; d.b.h. to 10-15 cm; bark smooth, green-grey; branches spreading horizontally; young branches black, densely covered with short appressed hairs or rarely glabrous; old branches grey, sparsely covered with short appressed hairs to glabrous, striate. Petioles 3-5 mm long, 1-2 mm in diameter, densely covered with short appressed hairs or rarely glabrous, leaf lamina inserted on side, weakly grooved adaxially. Leaf lamina (8.5-)15-22 cm long, 3-8 cm wide, length:width ratio 2-3.5, narrowly obovate to obovate or narrowly elliptic to elliptic, papyraceous, glabrous to very sparsely covered with short appressed hairs abaxially, glabrous adaxially, dark green adaxially, light green abaxially, base broadly cuneate to rounded, apex acuminate, acumen ca. 1 cm long; midrib sparsely covered with short appressed hairs to glabrous adaxially, densely to sparsely covered with short appressed hairs or rarely glabrous abaxially; secondary veins 8-13 pairs, sparsely covered with short appressed hairs to glabrous on both sides. Rhipidia 1-2, on leafy branches. Flowering pedicels 5-12 mm long, ca. 2 mm in diameter, densely or rarely sparsely covered with short appressed hairs, light green. Lower bracts 1-3, ca. 1 mm long, ca. 0.5 mm wide, covered with short appressed hairs. Upper bract near the base of the pedicel or absent, ca. 0.5 mm long, ca. 0.5 mm wide, covered with short appressed hairs or rarely glabrous. Sepals 3-5 mm long, 2-3 mm wide, length:width ratio 1-2, narrowly to broadly triangular, base truncate, apex acute, densely covered with short appressed hairs or rarely sparsely covered with short appressed hairs, green, in mature flowers reflexed outwards, falling when in fruit. Corolla green when immature to light yellow with light red in center of tube at anthesis; tube 3-5 mm long, 4-6 mm in diameter, lobe:tube ratio 2.7-4.8, cupulate, covered with short appressed hairs or rarely glabrous outside, glabrous inside; lobes 15-19 mm long, 2-4 mm wide, length:width ratio 4.5-6.3, lorate to narrowly oblong, base truncate, apex round to acute, densely covered with short appressed hairs on the outside, less so on inside or rarely glabrous, coriaceous, spreading horizontally and then curving inwards, the margins folded outwards. Receptacle 4-5 mm in diameter. Stamens ca. 1 mm long; connective shield ca. 0.1 mm long, glabrous, light yellow, those of innermost whorl elongated and stretched against the ovary wall. Ovary 1-2 mm long, ca. 1 mm wide; stigma 3-4 mm, glabrous to sparsely covered with short erect hairs, light green. Fruiting pedicels 2-3 cm long, 3-4 mm in diameter, densely to sparsely covered with short erect hairs. Fruits 4-10 cm long, 1-3 cm in diameter, length:width ratio 3.6-4.5, narrowly ellipsoid, apiculate, apicule ca. 1 cm, 6-ribbed, glabrous, heavily speckled with white and yellow; pericarp ca. 3 mm thick. Seeds 15-20 mm long, ca. 10 mm in diameter, irregularly ellipsoid; testa smooth, light brown; hilum not seen.