Uvariodendron dzomboense Dagallier, Q.Luke & Couvreur, PhytoKeys 174: 114 (2021)

Dagallier, Leo-Paul M. J., Mbago, Frank M., Couderc, Marie, Gaudeul, Myriam, Grall, Aurelie, Loup, Caroline, Wieringa, Jan J., Sonke, Bonaventure & Couvreur, Thomas L. P., 2023, Phylogenomic inference of the African tribe Monodoreae (Annonaceae) and taxonomic revision of Dennettia, Uvariodendron and Uvariopsis, PhytoKeys 233, pp. 1-200 : 1

Uvariodendron dzomboense Dagallier, Q.Luke & Couvreur, PhytoKeys 174: 114 (2021)

Figs 17 , 18

Type.

Kenya - Coast • S.A. Robertson MDE207 (holotype: K! (no barcode); isotypes: EA!, MO!, WAG! (WAG0065798)), Kwale District - Dzombo Hill; 4°26'S, 39°13'E; alt. 300 m; 07 Feb. 1989 .

Description.

Tree 4-7 m tall, D.B.H. unknown; young branches sparsely pubescent to glabrous, old branches glabrous; leaf bud ‘eragrostiform’, composed of 5, distichous, longitudinally folded, velutinous scales. Leaves with margin slightly revolute. Petiole 3-4 mm long, 1-1.5 mm wide, sparsely pubescent to glabrous. Leaf lamina 65-132 mm long, 20-45 mm wide, length:width ratio 2.9-3.6, elliptic to narrowly elliptic, coriaceous, base acute to slightly decurrent, apex attenuate, surface above glabrous, surface below sparsely pubescent to glabrous when young, glabrous when old; midrib impressed above, raised below, glabrous above, slightly pubescent to glabrous below; secondary veins 12-13 pairs, weakly brochidodromous, impressed above, raised below; tertiary veins reticulate. Inflorescences borne on trunk and branches, composed of 1 flower. Flower pedicel 8-30 mm long, 2-2.5 mm in diameter, densely pubescent. Flowers bisexual, buds globose, sessile, ca. 4 mm high, ca. 4.5 mm in diameter, sparsely pubescent. Bracts 6 at base of the pedicel in flower bud, generally the uppermost remaining towards the lower half of the pedicel on mature flower, 5-6 mm long, 5-8 mm wide, ovate, pubescent to shortly pubescent outside, glabrous inside. Sepals 3, 5-7 mm long, 4.5-7 mm wide, fused at base, pubescent to shortly pubescent outside, glabrous inside, color unknown. Outer petals 3, ca. 16 mm long, ca. 9 mm wide, length:width ratio ca. 1.8, ovate, shortly velutinous outside, glabrous inside, color unknown. Inner petals 3, ca. 18 mm long, ca. 8 mm wide, length:width ratio ca. 2.3, obovate, shortly velutinous outside, glabrous inside, color unknown. Stamens 700 to 1000, 2 mm long, 0.5 mm wide, anthers linear, connective prolongation truncate. Carpels 50 to 75, ca. 2 mm long, 1-1.5 mm wide, densely pubescent, free; stigma unknown. Fruiting pedicel ca. 14 mm long, ca. 4 mm in diameter, pubescent. Monocarps (unripe?) ca. 35, ca. 15 mm long, ca. 10 mm wide, length:width ratio ca 1.5, ovoid, densely pubescent, golden brown, sessile. Seeds (unripe?) ca. 5 per monocarp, uniseriate, ca. 4.5 mm long, ca. 10 mm wide.

Distribution.

Endemic to Somalia-Masai Region. Only known from one locality in Kenya: Dzombo Hill.

Habitat and ecology.

Moist semi-deciduous forest. Soil: igneous intrusion. Altitude: 270-300 m a.s.l.

Phenology.

Flowers collected in January and June. Fruits collected in February.

Notes.

This species differs from the other Uvariodendron species by the combination of small (i.e. less than 150 mm long) narrowly elliptic to elliptic leaves and 50-75 densely pubescent carpels. It differs from Ud. kirkii by its smaller leaves (132 mm maximum versus 210 mm maximum) and higher number of carpels (50-75 versus 7-20).

Preliminary conservation status.

Previous work estimated the EOO and AOO of this species to be less than 6 km2, and assigned a preliminary status of Endangered EN B1ab(iii)+2ab(iii) ( Dagallier et al. 2021).

Additional specimens examined.

Kenya - Coast • W.R.Q. Luke 1654 (EA, K); Kwale District, Dzombo Forest Reserve ; 4°25'S, 39°13'E; alt. 270 m; 06 Jan. 1989 • W.R.Q. Luke 2884 (EA, K); Kwale District, Dzombo Forest Reserve ; 4°25'S, 39°13'E; alt. 271 m; 04 Oct. 1991 • W.R.Q. Luke 3370 (EA); Kwale District, Dzombo Forest Reserve ; 4°25'S, 39°13'E; alt. 272 m; 12 Nov. 1992 • W.R.Q. Luke 7443 (EA); Kwale District, Dzombo ; 4°25'S, 39°12'E; alt. 270 m; 28 Jun. 2001 .

Figures

Figure 17. Uvariodendron dzomboense Dagallier, Q. Luke & Couvreur A leaf, upper side B petiole and base of leaf, upper side C flower bud showing bracts, side view D flower, two outer petals and three outer petals removed E fruit with young monocarps. A-C Luke 7443 D, E Robertson MDE 207. Photos Leo-Paul Dagallier.

Figure 18. Distribution map of Uvariodendron dzomboense. Shades of grey represent elevation, from white (sea level) to darker grey (higher elevation). The inset shows the extent of the map over Africa.