Uvariopsis dioica (Diels) Robyns & Ghesq., Ann. Soc. Sci. Bruxelles, Ser. B 53: 321, 1933

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 : 419-422

Uvariopsis dioica (Diels) Robyns & Ghesq., Ann. Soc. Sci. Bruxelles, Ser. B 53: 321, 1933

Figs 127 , 133 ; Map 16C

≡ Tetrastemma dioicum Diels, Bot. Jahrb. Syst. 38(3): 241, 1906.

Type.

Cameroon. Littoral Region; Ed Winkler H. 909, Nov 1904: lectotype, designated here: B[B 10 0153121] .

Description.

Tree to shrub, 6-20 m tall, d.b.h. 14-40 cm; stilt roots or buttresses absent. Indumentum of simple hairs; old leafless branches glabrous, young foliate branches pubescent to glabrous. Leaves: petiole 2-5 mm long, 1-2.5 mm in diameter, sparsely pubescent to glabrous, narrowly grooved, blade inserted on top of the petiole; blade 11.1-24.5 cm long, 3.8-9.2 cm wide, elliptic to obovate, apex attenuate to acuminate, acumen 0.7-3 cm long, base rounded to acute to decurrent, coriaceous, below sparsely pubescent to glabrous when young, glabrous when old, above glabrous when young and old; midrib sunken or flat, above glabrous when young and old, below glabrous to pubescent when young, glabrescent when old; secondary veins 6 to 14 pairs per side, glabrous above; tertiary venation reticulate. Individuals unisexual, monoecious, dimorphic. Flowers with 6 perianth parts in 2 whorls. Male inflorescences cauliflorous, 5 to 20-flowered or more, on thick clumps on the lower part of the trunk; male flowers: pedicel 11-50 mm long, 1-2 mm in diameter, sparsely pubescent to glabrous; bracts 2, one basal and one upper towards the middle or lower half of pedicel, basal bract minute, ca. 1 mm long, ca. 1 mm wide; upper bract 0.5-1.5 mm long, 1-2 mm wide; sepals 2, valvate, basally fused, 1.5-4.5 mm long, 2.5-11 mm wide, circular to broadly ovate, apex acute or rounded, base truncate, purple, pubescent to sparsely pubescent outside, glabrous inside, margins flat; petals free, 4 in one whorl, 6-11 mm long, 3.5-8 mm wide, ovate to elliptic, apex acute, base truncate, wine red to dark brownish-red, margins flat, pubescent to glabrous outside, glabrous inside; stamens ca. 300, in 20 to 25 rows on a convex receptacle, 0.4-0.5 mm long; connective minute, glabrous; staminodes absent. Female inflorescences cauliflorous, axillary, clumps of 6 to 10 flowers or more, on thick clumps on the lower part of the trunk; female flowers: pedicel 10-50 mm long; 2-3 mm in diameter, sparsely pubescent to glabrous; in fruit 8-55 mm long, 2-4 mm in diameter, sparsely pubescent to glabrous; bracts 2, one basal and one upper towards the middle or lower half of pedicel, basal bract minute, ca. 1 mm long, ca. 1 mm wide; upper bract 0.5-1.5 mm long, 1-2 mm wide; sepals 2, valvate, basally fused, 2-5 mm long, 2-11 mm wide, circular to broadly ovate, apex acute or rounded, base truncate, purple, pubescent to sparsely pubescent outside, glabrous inside, margins flat; petals free, 4, in one whorl, 7-20 mm long, 4-15 mm wide, ovate to elliptic, apex acute, base truncate, wine red to dark red-brownish outside, margins flat, pubescent to glabrous outside, glabrous inside; carpels free, 100 to 280, ovary 1.5-2.5 mm long, stigma coiled bilobed, glabrous. Monocarps stipitate, stipes 0-2 mm long, ca. 4 mm in diameter; monocarps 2 to 5, 21-60 mm long, 30-35 mm in diameter, ovoid to cylindrical, apex rounded, sparsely pubescent to glabrous, smooth, not ribbed, pale brownish grey to yellow to red; seeds 5 to 8 per monocarp, 15-22 mm long, ca. 15 mm in diameter, ellipsoid; aril absent.

Distribution.

A central African species, from Nigeria to Republic of the Congo; in Cameroon known from the Central, East, Littoral, South and South-West regions.

Habitat.

A common species, in lowland primary or old secondary rain forests. Altitude 50-800 m a.s.l.

Local and common names known in Cameroon.

None recorded.

IUCN conservation status.

Not evaluated.

Uses in Cameroon.

None reported.

Notes.

Uvariopsis dioica resembles U. pedunculosa and U. solheidii by its elliptic to obovate shape of its leaves and the acute to rounded shape of the leaf base and attenuate to acuminate apex. However, Uvariopsis dioica has flowers borne in thick clumps of 5 to 20 flowers on the lower (less than 3 m) part of the trunk (versus 1 or 2 flowers per inflorescence on think clumps) and with 100 to 240 carpels (versus less than 100 in most other species). Clustered inflorescences on the basal part of the trunk is also found in the Cameroonian endemic species Uvariopsis korupensis , but U. dioica has smaller leaves (11-25 cm long vs. 28-62 cm long).

Robyns and Ghesquière (1933) indicate two types for U. dioica : Winkler 908 and 909. We only located sheet 909 in B, while sheet 908 was not seen (nor is it available online), and is thus probably destroyed.

Contrary to what the name suggests, Uvariopsis dioica is not dioecious but monoecious. The specific epithet probably comes from a misinterpretation of the species based only on the original type specimens composed of a sheet with male flowers (Winkler 908) and a sheet with female flowers (Winkler 909). Unisexual individuals might exist, but all the specimens we examined have both female and male flowers.

Uvariopsis pedunculosa (Diels) Robyns & Ghesq. ( Tetrastemma pedunculosum Diels) was synonymized by Keay under U. dioica ( Keay 1952) but is here regarded as a separate species.

Specimens examined.

Central Region: Reserve forestière de Makak au bord du Nyong, 3.59°N, 11.03°E, 14 December 1967, Bamps P.R.J. 1458 (P,YA); Ndiki, 4.77°N, 10.83°E, 01 November 1938, Jacques-Félix H. 2493 (P); Foret de Mambe près Boga (30 km N Eseka), 3.9°N, 10.78°E, 08 December 1973, Letouzey R. 12290 (K,P,YA); Mfiki (Ndo par Esse), 4.31°N, 11.96°E, 09 November 1969, Letouzey R. 9541 (P,WAG); Etwa 115 km NO Juande , 4.48°N, 12.35°E, 01 January 1914, Mildbraed G.W.J. 8260 (K) . East Region: Réserve de faune du Dja Djolimpoun , 3.17°N, 13.18°E, 17 April 1995, Sonké B. 1505 (BR,YA) . Littoral Region: Mambe Massif above Boga village 100 km along road from Yaoundé to Ed 3.90°N, 10.77°E, 19 June 2014, Couvreur T.L.P. 654 (WAG,YA); Mambe Massif above Boga village 100 km along road from Yaoundé to Ed 3.90°N, 10.77°E, 20 June 2014, Couvreur T.L.P. 659 (WAG,YA); Au sud de Ngola (8 km Est de l’embouchur de la Sanaga), 3.55°N, 9.698°E, 05 January 1974, Letouzey R. 12580 (P,YA); Ed 3.81°N, 10.13°E, 01 January 1904, Winkler H. 909 (B) . South Region: N’koladom village 4 km on the road (old road) from Nkoemvone to Ambam , 2.8°N, 11.15°E, 27 November 1974, de Wilde J.J.F.E 7754 (K,P,WAG); Nkoemvone, 2.81°N, 11.13°E, 05 June 1975, de Wilde J.J.F.E 8270a (BR,MO,P,WAG); Station de cacaoyer de N’koemvone 14 km On the road from Ebolowa to Ambam, 2.8°N, 11.13°E, 12 December 1975, de Wilde J.J.F.E 8709 (BR,MO,P,WAG,YA); Nkomo près Ngoase au S de la rive Lobe, 3.26°N, 12.02°E, 13 February 1962, Letouzey R. 4219 (K,P,YA); Nkomo près Ngoase au S de la rive Lobe, 3.26°N, 12.02°E, 14 February 1962, Letouzey R. 4230 (BR,P,YA); Près Mevous 50 km SE d’Ebolowa sur piste d’Evindissi, 2.6°N, 11.46°E, 30 January 1970, Letouzey R. 9934 (BR,K,P,YA) . South-West Region: ca 40 minutes walk N then E from Njonji Hunters path to Lake Njonji, 4.13°N, 8.993°E, 18 November 1993, Cheek M. 5482 (K,YA); ca 40 minutes walk N then E from Njonji Hunters path to Lake Njonji , 4.13°N, 8.993°E, 19 November 1993, Cheek M. 5501 (K,MO,WAG,YA); Entre Ayong et Baro 20 km SW Nguti, 5.2°N, 9.32°E, 10 June 1975, Letouzey R. 13790 (P,YA); Bibundi, 4.21°N, 8.988°E, 01 November 1928, Mildbraed G.W.J. 10647 (K); Pente SW Mt Cameroun ME Bakingili WNW Limbé, 4.07°N, 9.04°E, 09 December 1984, Villiers J.-F. 2429 (P,YA) ; Limbe W of Njonji Lake , 4.13°N, 9.016°E, 27 January 1994, Wieringa J.J. 2029 (WAG) .

Figures

Map 16. A Uvariopsis conge nsis B Uvariopsis dicaprio C Uvariopsis dioica D Uvariopsis etugeana E Uvariopsis korupensis F Uvariopsis pedunculosa G Uvariopsis sessiliflora H Uvariopsis solheidii I Uvariopsis submontana. White borders represent region limits in Cameroon; green patches represent protected areas (see methods and Suppl. material 1: Fig. S 1).

Figure 127. Uvariopsis bakeriana A leaf, top view B detail of male flower, 2 petals removed C petal, inner view D carpel, side view, front view and detail of ovules E monocarp. Uvariopsis dioica F leaf, top view G male flowering pedicels and flowers H detail of male flower, 2 petals removed I stamen J female flowering pedicel K detail of female flower, all 4 petals removed L carpel, front view and detail of ovules M fruits A-E from Brenan 9409 F-L from Keay 28066 M from Letouzey 4230. Drawings by Helene Lamourdedieu, Publications Scientifiques du Museum national d'Histoire naturelle, Paris.

Figure 133. Uvariopsis dioica A habit, note the cluster of fruits at the base of the trunk B leaf base, under side C leaf base, upper side D cluster of female flowers E detail of male flower F cluster of fruits G longitudinal section of monocarp A-C, F-G Couvreur 654, Mambe, Cameroon D, E Stevart 4792, Gabon. Photos A-C, F, G Thomas L. P. Couvreur D, E Tariq Stevart.