Uvariopsis Engl., Notizbl. Konigl . Bot. Gart. Berlin 2: 298, 1899

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 : 404-405

Uvariopsis Engl., Notizbl. Konigl. Bot. Gart. Berlin 2: 298, 1899

= Tetrastemma Diels Bot. Jahrb. Syst. 38(3): 241 1906; Thonnera De Wild., Ann. Mus. Congo Belge, Bot. sér. 5, 3[1]: 86, 1909

Type species.

Uvariopsis zenkeri Engl.

Description.

Trees, 3-25 m tall, d.b.h. up to 40 cm; stilt roots or buttresses absent. Indumentum of simple hairs or glabrous. Leaves: petiole 2-8 mm long, 1-6 mm in diameter; blade 10-52 cm long, 3.5-14 cm wide, ovate, elliptic, obovate or oblong, apex acuminate to abruptly acuminate, acumen 0.7-2 cm long, base cuneate to cordate; midrib sunken or flat; secondary veins 6 to 20 pairs; tertiary venation reticulate. Flowers unisexual, monoecious, male and female flowers similar or dissimilar, or bisexual (in one species not present in Cameroon), with (5) 6 perianth parts in 2 whorls. Inflorescences ramiflorous or cauliflorous, flower buds globose or conical, 1 to 6(50) per inflorescence; pedicel 1-450 mm long; in fruit 3-450 mm long; bracts 1 to 4, one basal and one upper, or all basal, 1-2 mm long; sepals 2, valvate (imbricate), free or basally fused, 1.5-10 mm long, ovate to semi-circular, apex acute, acuminate or attenuate, base truncate; petals free or basally fused, (3)4, valvate, 2-45 mm long, 2.5-17 mm wide, oblong, ovate, elliptic or linear, apex acuminate or attenuate, base truncate; stamens 100 to 1000, in 9 to 30 rows, 1-2 mm long, oblong to elongated; connective reduced or absent, glabrous; staminodes absent; carpels free, 15 to 280, 1-4 mm long, stigma ovoid, coiled or flat, glabrous. Monocarps sessile or stipitate, stipes 1-10 mm long; monocarps 2 to 25, 15-80 mm long, 9-55 mm in diameter, cylindrical, ellipsoid or globose, apex rounded or apiculate, smooth, verrucose or bumpy; seeds 4-25 mm long, 3-15 mm in diameter, ellipsoid; aril absent.

Taxonomy.

Le Thomas (1969b); Gereau et Kenfack (2000); Kenfack et al. (2003); Dagallier et al. (in prep.).

A genus with 18 species, 13 of which occur in Cameroon, three being endemic, making Cameroon a center of diversity for this genus.

Uvariopsis is distinguished from other Annonaceae genera in Cameroon by having 2 sepals and 4 petals in a single whorl (except for U. congolana which has 3 petals but 2 sepals). Uvariopsis is unisexual and monoecious (male and female flowers on same individual), except for the East African species U. bisexualis Verdc. which is bisexual ( Verdcourt 1986). Important characters to distinguish the different species of Uvariopsis are the shape of the flower buds (which can be conical or globose) and whether the petals are basally fused or free ( Gereau and Kenfack 2000; Kenfack et al. 20 03; Gosline et al. 2022). Uvariopsis can be divided in two main groups: species with male or hermaphrodite flowers occurring on branches, and then the flowers are small (petals shorter than 7 mm), and species with large flowers (petals longer than 7 mm) all cauliflorous.

The species Dennettia tripetala Bak. f. was suggested to be congenic with Uvariopsis ( Kenfack et al. 2003), but recent phylogenetic analyses showed it should be kept in a genus of its own which is followed here (Dagallier et al. in prep; see under that name).