Isolona cooperi Hutch. & Dalziel ex G.P.Cooper & Record, Bull. Yale Univ. School For. No. 31: 15, 1931

Couvreur, Thomas L. P., Dagallier, Leo-Paul M. J., Crozier, Francoise, Ghogue, Jean-Paul, Hoekstra, Paul H., Kamdem, Narcisse G., Johnson, David M., Murray, Nancy A. & Sonke, Bonaventure, 2022, Flora of Cameroon - Annonaceae Vol 45, PhytoKeys 207, pp. 1-532 : 137-139

Isolona cooperi Hutch. & Dalziel ex G.P.Cooper & Record, Bull. Yale Univ. School For. No. 31: 15, 1931

Fig. 35 ; Map 5B

Type.

Liberia. Montserrado; near Firestone plantations, along Dukwai road, Cooper G.P. 417, 7 May 1929: lectotype, designated by Couvreur (2009), p. 148: GH[GH00286760]; isotypes: F[F0093217]; FHO[FHA00095994]; G[GH00286760]; K n.v.; NY[NY00026103]; WIS[WIS00000299MAD] .

Description.

Tree, 6-18 m tall, d.b.h. 20 cm; stilt roots or buttresses absent. Indumentum absent; old leafless branches glabrous, young foliate branches glabrous. Leaves: petiole 1-5 mm long, 2-3 mm in diameter, glabrous, grooved, blade inserted on top of the petiole; blade 15-29 cm long, 6-15 cm wide, oblong to obovate, apex acuminate, acumen 1-2 cm long, base cuneate to rounded, subcoriaceous, below glabrous when young and old, above glabrous when young and old, concolorous; midrib raised, above glabrous when young and old, below glabrous when young and old; secondary veins 9 to 18 pairs, glabrous below; tertiary venation reticulate. Individuals bisexual; inflorescences cauliflorous or ramiflorous on young foliate branches, axillary. Flowers with 9 perianth parts in 2 whorls, 1 to 2 per inflorescence; pedicel 14-25 mm long, 1 mm in diameter, glabrous; in fruit 16-27 mm long, 2 mm in diameter, glabrous; bracts 2 to 4, all basal, 1 mm long, 1mm wide; sepals 3, valvate, free, 2 mm long, 2 mm wide, ovate, apex rounded, base truncate, green, glabrous outside, glabrous inside, margins flat; petals basally fused, tube 6-11 mm long, inner and outer whorl not differentiated, equal; lobes 8-15 mm long, 4-6 mm wide, oblong, apex acute to rounded, green, margins flat, glabrous outside, glabrous inside, spreading horizontally; stamens numerous, in 3 to 4 rows, 2 mm long, broad; connective discoid, glabrous, green; staminodes absent; carpels fused into a single structure, 3 mm long, stigma capitate, glabrous. Fruit syncarpous, sessile, 30-90 mm long, 15-30 mm in diameter, ellipsoid, apex apiculate, glabrous, smooth, constricted over seeds in dried material, smooth when fresh, orange with white spots when ripe; seeds not counted, 10-15 mm long, 5-10 mm in diameter, ellipsoid; aril absent.

Distribution.

A mainly West African species, from Liberia to Ghana, with a few specimens from Cameroon and one from Gabon; in Cameroon known from South and South-West regions.

Habitat.

A rare species in Cameroon; in lowland primary and secondary forests, also along rivers, on sandy soils. Altitude 0-300 m a.s.l.

Local and common names known in Cameroon.

None recorded.

IUCN conservation status.

Least Concern (LC) ( Cosiaux et al. 2019r).

Uses in Cameroon.

None reported.

Notes.

Isolona cooperi is distinguished by its completely glabrous leaves, young foliate branches and flowers and with the leaf blade inserted on top of the petiole. In addition, the flowers emit a very strong sweet scent, noticeable even in dried material. It has a smooth corolla in dried material and corolla lobes with straight margins. Isolona cooperi is similar to I. hexaloba by the shape of its flowers, but the latter differs by its blade inserted sideways to the petiole and the absence of the strong sweet scent. Finally, I. cooperi resembles I. campanulata by the shape of the fruits.

Specimens examined.

South Region: Bipindi, 3.08°N, 10.41°E, 01 February 1910, Zenker G.A. s.n. (F). South-West Region : Korup National Park, 5.06°N, 8.855°E, 10 March 1998, Kenfack D. 1063 (MO,WAG) .

Figures

Map 5. A Isolona congolana B Isolona cooperi C Isolona dewevrei D Isolona hexaloba E Isolona pilosa F Isolona pleurocarpa G Isolona thonneri H Isolona zenkeri I Letestudoxa bella. White borders represent region limits in Cameroon; green patches represent protected areas (see methods and Suppl. material 1: Fig. S 1).

Figure 35. Isolona cooperi A flowering branch B leaf, lower view C detail of petiole and axillary inflorescence D flower bud E flower, side view F flower, semi side view G flower, bottom view H transversal section showing androecium and stigma I stamen, front view J fruit (dried) K fruit, part of pericarp removed showing ruminate section of seed (fresh) L seed with seed coat partially removed showing ruminations A-C from J. J. F. E. de Wilde 3644 D-I from fresh material collected at the Utrecht University Botanical Garden J, L from de Koning 149 K from Breteler 7458. Drawings Hans by Vries (Couvreur 2009, fig. 21, p. 42).