Uvariastrum zenkeri Engl. & Diels, Bot. Jahrb. Syst. 34: 473, 1907

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 : 380-383

Uvariastrum zenkeri Engl. & Diels, Bot. Jahrb. Syst. 34: 473, 1907

Figs 118 , 119 ; Map 15A

= Uvariastrum zenkeri Engl. & Diels var. nigritanum Baker f., Cat. Talbot’s Plants 3, 1913. Type. Nigeria. Cross River State: Oban district, recd. at Paris 21 Feb 1912, Talbot P.A. 1341; lectotype, designated by Couvreur (2014), p. 28: K[K001081866]; isotypes: FHO [accession number 15560, barcode 3586]; P [P01983332].

= Uvariastrum pynaertii De Wild., Ann. Mus. Congo Belge, Bot. sér. 5, 3(1): 74, 1909. Type. Democratic Republic of the Congo. Equateur, Eala, Pynaert L.A. 1234, Mar 1907: lectotype designated by Le Thomas (1969b), p. 292, sheet designated by Couvreur (2014), p. 28: BR[BR0000008824288]; isolectotypes: BR[BR0000008824295, BR0000008824301]; S[S12-22788].

Type.

Cameroon. South Region; Bipindi, Zenker G.A. 2935, 1904: lectotype, designated by Couvreur (2014), p. 28: B[B100153114]; isolectotypes: B[B100190283]; BM,[BM000554069]; BR[BR0000014035722]; COI[COI00077201]; GOET[GOET005731]; G[G00011742, G00011744]; K[K000198808]; L[L0191076]; M[M0089220]; MA[ MA215566 -3]; P[P00315826]; S[S12-22789]; WAG[WAG0057973]; WU[WU0025789]; Z [Z000034578, Z000034577] .

Description.

Tree to shrub, 20-30 m tall, d.b.h. 20-30 cm; stilt roots or buttresses absent. Indumentum of simple hairs; old leafless branches glabrous, young foliate branches sparsely pubescent to glabrous. Leaves: petiole 2-3 mm long, ca. 2 mm in diameter, sparsely pubescent, not grooved, blade inserted on top of the petiole; blade 12-22 cm long, 3-5 cm wide, elliptic to obovate, apex acuminate, acumen 1-2 cm long, base cuneate to rounded, coriaceous, below sparsely pubescent when young, glabrous when old, above glabrous when young and old, concolorous; midrib sunken or flat, above pubescent when young, glabrous when old, below sparsely pubescent to densely pubescent when young, sparsely pubescent to densely pubescent when old; secondary veins 11 to 17 pairs, glabrous above; tertiary venation reticulate. Individuals bisexual; inflorescences cauliflorous or ramiflorous on young foliate or old leafless branches, axillary. Flowers with 9 perianth parts in 3 whorls, 1 to 2 per inflorescence; pedicel 13-30 mm long, 1-2 mm in diameter, sparsely pubescent to glabrous; in fruit 15-30 mm long, 2-5 mm in diameter, glabrous; bracts 3, all basal, 5 mm long, 3-4 mm wide; sepals 3, reduplicate-valvate, free, 15-25 mm long, 8-15 mm wide, ovate, apex acute, base truncate, light brown, sparsely pubescent to glabrous outside, pubescent and glabrous towards center inside, margins recurved; petals free, sub equal; outer petals 3, 20-35 mm long, 8-15 mm wide, elliptic to ovate, apex acute, base truncate, yellow, margins flat, densely pubescent outside, pubescent except towards center inside; inner petals 3, valvate, 15-25 mm long, 7-10 mm wide, ovate, apex acute, base cuneate, claw mm long, white turning bright yellow to orange, light grey when old, margins flat, densely pubescent outside, pubescent except towards center inside; stamens numerous, 2-4 mm long, linear; connective discoid, pubescent, red; staminodes absent; carpels free, (1-3) 5 to 15, ovary 3-5 mm long, stigma capitate, sparsely pubescent to glabrous. Monocarps shortly stipitate, stipes 2-5 mm long, ca. 5 mm in diameter; monocarps 2 to 5, 80 mm long, 25 mm in diameter, oblong, apex acute, sparsely pubescent to glabrous, longitudinally 4 to 6 ribbed, sometimes more finely ribbed, light green-grey with dashed of white when ripe; seeds 20 to 27 per monocarp, 15-20 mm long, 10-15 mm in diameter, flattened ellipsoid; aril absent.

Distribution.

A widespread species in Central Africa, from extreme southeast of Nigeria to the Republic of Congo, and Democratic Republic of Congo. In Cameroon known from the East, South, Central, South-West regions.

Habitat.

A common species, in primary or secondary lowland rain forest, mainly on non-inundated soils, but also on marshy or sandy soils. Altitude 0-400 m a.s.l.

Local and common names known in Cameroon.

None recorded.

IUCN conservation status.

Least Concern (LC) ( Cosiaux et al. 2019a v).

Uses in Cameroon.

None reported.

Notes.

Uvariastrum zenkeri is easily distinguished by the sepals that dry black and the large leaves with the blade inserted on top of the petiole. The black color of the dried sepals is related to their glabrous or sparsely pubescent outer side, whereas it is pubescent in U. insculptum and U. pierreanum .

Specimens examined.

East Region: Dja reserve , 3.20°N, 12.79°E, 04 November 1994, Fogiel M.K. 1039 (MO,P). Littoral Region : Ebo Wildlife Reserve Djuma permanent camp, 4.34°N, 10.23°E, 14 February 2014, Couvreur T.L.P. 624 (WAG,YA); Douala (Route Razel), 4.05°N, 9.7°E, 01 January 1955, Endengle E. s.n. (P,YA). South Region : 41 kmN of Kribi 5 km E of Edea road forest track Fifinda-Bella old secondary forest, 3.21°N, 10.06°E, 06 February 1970, Bos J.J. 6266 (BR,C,K,LD,P,WAG,YA); Entre 15 et 25 km au SW de Zingui (soit à 45 km au SSE de Kribi), 2.82°N, 10.97°E, 22 March 1968, Letouzey R. 9121 (P,YA); Bipindi, 3.08°N, 10.42°E, 01 January 1902, Zenker G.A. 2438 (B,COI,G,K,L,MO,P,S,WAG); Bipindi, 3.08°N, 10.42°E, 01 January 1904, Zenker G.A. 2935 (B,BM,COI,G,K,L,M,P,WAG); Bipindi, 3.08°N, 10.41°E, 01 January 1906, Zenker G.A. 3248 (K); Bipindi, 3.08°N, 10.42°E, 01 January 1907, Zenker G.A. 3289 (B,L,P,S); Bipindi, 3.08°N, 10.42°E, 01 January 1908, Zenker G.A. 3409 (COI,G,L,M,MO,P,S); Bipindi, 3.08°N, 10.42°E, 01 January 1912, Zenker G.A. 4473 (B,COI,G,L,M,P,S); Bipindi, 3.08°N, 10.41°E, 01 January 1914, Zenker G.A. 481 (B,BR,C,F,G,GH,M,P,S,U,WAG). South-West Region : Mabeta Moliwe, 3.96°N, 9.233°E, 02 April 1992, Bongyu J. 42 (K,P); Korup National Park , 5.06°N, 8.855°E, 12 January 1998, Kenfack D. 1008 (MO,P,WAG); Boa, 4.4°N, 9°E, 04 May 1994, Ndam N. 1248 (K); Mokoko Forest Reserve , 4.46°N, 9.066°E, 19 April 1994, Tchouto Mbatchou G.P. 1108 (K); Ndian River at PAMOL field 69 and transect P, 5.01°N, 8.833°E, 24 January 1985, Thomas D.W. 4334 (K,MO,P,YA); Korup National Park , 4.98°N, 8.85°E, 12 January 1979, Thomas D.W. 604 (K); Korup National Park , 5.05°N, 8.766°E, 10 June 1988, Thomas D.W. 8094 (L,P,WAG,YA); West bank of the Onge River , 4.28°N, 8.966°E, 07 November 1993, Thomas D.W. 9772 (K,MO,P,WAG,YA); Korup National Park, 5°N, 8.8°E, 04 February 2000, van der Burgt X.M. 590 (G,WAG,YA); Korup National Park, 5°N, 8.8°E, 19 March 2004, van der Burgt X.M. 674 (BR,G,K,MO,P,WAG,YA) .

Figures

Map 15. A Uvariastrum zenkeri B Uvariodendron angustifolium C Uvariodendron calophyllum D Uvariodendron conniven s E Uvariodendron fuscum F Uvariodendron fuscum var. giganteum G Uvariodendron molundense H Uvariopsis bakeriana I Uvariopsis citrata. White borders represent region limits in Cameroon; green patches represent protected areas (see methods and Suppl. material 1: Fig. S 1).

Figure 118. Uvariastrum pierreanum A habit B flower, side view, one outer and one inner petal removed C flower, side view D flower bud, note folded sepal margins J young fruits. Uvariastrum zenkeri F habit, U. zenkeri is the smaller tree, note yellow flowers E flower, top view G base of leaf blades, lower side H base of leaf blade, upper side, note leaf blade inserted on top of the petiole I fruit A-D Couvreur 454, Lele, Cameroon E, G, H Couvreur 624, Ebo, Cameroon F Couvreur 877, Gabon I Couvreur 572, Gabon J Couvreur 590, Gabon. Photos Thomas L. P. Couvreur.

Figure 119. Uvariastrum zenkeri A leaf B, C cauliflorous flowers D detail of flower with three petals removed E detail of receptacle F sepals G carpels H stamens I detail of monocarp. Drawings by Helene Lamourdedieu, Publications Scientifiques du Museum national d'Histoire naturelle, Paris; modified from Le Thomas (1969 b, pl. 52, p. 291, pro parte).