Isolona cooperi
Tree or shrub to 6-10(-18) m high; d.b.h to 20 cm; bark coarsely rugulate, brown; young branches drying black, glabrous, smooth; old branches dark brown, glabrous, striate. Petioles 1-5 mm long, 2-3 mm in diameter, glabrous, verruculose, leaf lamina inserted on top, very weakly and narrowly grooved adaxially. Leaf lamina (15-)17-27(-29) cm long, 6-12(-15) cm wide, length:width ratio 2.2-3.9; oblong or narrowly oblong to obovate or narrowly obovate, subcoriaceous, glabrous on both sides, pale green below, dark green somewhat shiny above, base rounded to broadly cuneate, apex acuminate, acumen 1-2 cm long; midrib raised and glabrous adaxially, very prominent and glabrous abaxially; secondary veins 9-18 pairs, prominent below, printed above, straight then abruptly curved or uniformly curved upwards, loop forming towards margin. Rhipidia 1-2, on leafy branches and/or trunk. Flowering pedicels 14-25 mm long, ca. 0.5 mm in diameter, glabrous. Lower bracts 2-4, 0.5-1 mm long, 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, coriaceous, pressed against tube, falling when in fruit; margins glabrous. Corolla green when immature to bright yellow and emitting a very strong sweet scent at anthesis; tube 6-11 mm, 3-5 mm in diameter, lobe:tube ratio 1.2-1.9, cupulate, glabrous; lobes 8-15 mm long, 4-6 mm wide, length:width ratio 1.6-3.2, narrowly oblong to oblong, apex acute, rounded at tip, glabrous, coriaceous, spreading horizontally, margins flat. Receptacle 4-5 mm in diameter. Stamens ca. 2 mm long; connective shield ca. 0.2 mm long, glabrous, those of innermost row extended over adjacent ovary wall. Ovary ca. 2.5 mm long, ca. 1.5 mm wide; stigma ca. 1.5 mm in diameter, glabrous. Fruiting pedicels 16-27 mm long, ca. 2 mm in diameter, glabrous. Fruits (3-)8-9 cm long, 1.5-3.0 cm in diameter, length:width ratio 2-4.5, ellipsoid to narrowly ellipsoid, apex apiculate, apicule ca. 1 cm long, smooth, glabrous, orange with white spots when mature; pericarp 1-2 mm thick, constricted over seeds in dried material but not in fresh material. Seeds 10-15 mm long, 5-10 mm in diameter, ellipsoid, packed in white pulp; testa rough, dark brown; raphe slightly thickened; hilum 4-5 mm long, 1.5-2 mm wide, elliptical.
Isolona cooperi is distinguished by the following characters: leaves, young branches and flowers completely glabrous with the lamina inserted on top of the petiole, flowers emitting a strong sweet scent even in dried material, a smooth corolla in dried material and corolla lobes with flat margins. Isolona cooperi emits an extraordinary strong sweet smell at anthesis, which persists in herbarium material and even in spirit collections. It presents close morphological similarities to I. hexaloba by the shape of its flowers. The latter species is, however, distinct by the lamina inserted sideways to the petiole and by the lack of the strong sweet scent. Additonally, I. cooperi resembles I. campanulata by the shape of the fruits. The latter relationship is strongly supported by molecular evidence (Fig. 1). For a separation from I. campanulata see that species (no. 1).
In Liberia the bark has a magical use as a charm against witchcraft (Cooper and Record 1931; Burkill 1985).The grounded leaves are used as a tonic (Neuwinger 2000).
LC. Isolona cooperi is found in three forest reserves (Monogaga and Esen Epam, Ivory Coast; Cape Three Points, Ghana) and in two national parks (Banco, Ivory Coast; Korup, Cameroon). The species is well represented in herbaria with numerous recent collections. The “Least concern” category is therefore applied.
Isolona cooperi is recovered with strong support as sister to I. campanulata.
Liberia to Ghana, most common in Ivory Coast, once collected in western Cameroon; in primary or secondary lowland rain forest and along rivers, on sandy soil; at 0-300 m altitude.