Uvariodendron mossambicense Robson ex Dagallier & Couvreur, 2023

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 mossambicense Robson ex Dagallier & Couvreur sp. nov.

Figs 36 , 37

Type.

Mozambique - Manica • F. de A. Mendonça 2558A (holotype: WAG! (WAG.1418614); isotypes: COI! (COI00085396), LISC), Chimoio, Cataratas do Rio Revue ; 19°37'S, 33°31'E; 23 Oct. 1944 .

Diagnosis.

Ud. mossambicense closely resembles Ud. dzomboense by its narrowly elliptic and small (less than 140 mm long) leaves with acute to slightly decurrent base. However, Ud. mossambicense has flower buds ca. 6 mm in diameter (vs ca. 4 mm in Ud. dzomboense ), covered by 2-5 velutinous bracts ca. 4 mm long (vs. 6 sparsely pubescent bracts 5-6 mm long). Ud. mossambicense has ca. 5 carpels (vs. 50-75 in Ud. dzomboense ) and monocarps with stipe ca. 12 mm long (vs. sessile monocarps) (Table 3 ). Ud. mossambicense can be differentiated from all the other species by the combination of the following characters: narrowly elliptic leaves less than 140 mm long with acute to slightly decurrent base, flowers with ca. 5 carpels and monocarps with stipe ca. 12 mm long.

Description.

Probably a small tree but height unknown, D.B.H. unknown; young branches pubescent to glabrous, old branches glabrous; leaf bud ‘eragrostiform’, composed of 7, distichous, longitudinally folded, velutinous scales. Petiole 3-5 mm long, ca. 1.5 mm wide, glabrous. Leaf lamina 80-135 mm long, 30-50 mm wide, length:width ratio ca. 3, narrowly elliptic, coriaceous, base acute to slightly decurrent, apex attenuate, surface above glabrous, surface below glabrous; midrib impressed above, raised below, glabrous above, glabrous below; secondary veins 10-16 pairs, brochidodromous, impressed above, raised below; tertiary veins reticulate. Inflorescences borne on branches, composed of 1 flower. Flowers bisexual, buds globose, sessile, ca. 6 mm high, ca. 6.5 mm in diameter, velutinous. Only flower bud seen. Bracts 2 to 5, upper bract ca. 4 mm long, ca. 7 mm wide, broadly ovate, appressed, half-enclosing the flower bud, velutinous outside. Sepals 3, 4-5 mm long, ca. 6 mm wide (measures taken from bud), broadly ovate, fused at base on almost 50 % of their length, forming a 3-lobed cupule, velutinous outside, glabrous inside. Outer petals 3, ca. 5 mm long, ca. 5 mm wide (measures taken from bud), length:width ratio ovate, velutinous outside. Inner petals 3, length, shape, indumentum and color unknown. Stamens numerous, length unknown, anthers linear. Carpels ca. 5, glabrous, free; stigma unknown, pubescent. Fruiting pedicel unknown. Monocarp 1 seen, ca. 37 mm long, ca. 9 mm wide, length:width ratio ca. 4.1, cylindrical, curved, slightly acuminate, glabrous, (monocarp found in the pocket of the specimen); stipitate, stipe ca. 12 mm long, ca. 3 mm wide, glabrate. Seeds 4 per monocarp, uniseriate, size and shape unknown.

Distribution.

Endemic to Somalia-Masai Region. Only known from one locality in Mozambique: Chimoio, near the falls of Revué river.

Habitat and ecology.

Unknown. Altitude around 100 m a.s.l.

Phenology.

Flowers and fruits collected in October.

Etymology.

The specific epithet comes from the country where the single specimen of this species was found.

Preliminary conservation status.

This species is known from a single location, not situated in a protected area. Its EOO and AOO are thus estimated lower than 4 km2. Although the botanical exploration of the country is continuously updated ( Hyde et al. 2021), this species is known from a single specimen collected more than 70 years ago. It is thus possible that this species is extinct. Following IUCN criterion B, we assigned this species a preliminary conservation status of Critically Endangered CR B1ab(iv)+2ab(iv).

Figures

Figure 36. Uvariodendron mossambicense Robson ex Dagallier & Couvreur A entire specimen sheet with young branch and leaves B leaf, top view C ' eragrostiform' apical bud D monocarp and flower buds. A-D Mendonca 2558 A (type). Photos Leo-Paul Dagallier.

Figure 37. Distribution map of Uvariodendron mossambicense. Shades of grey represent elevation, from white (sea level) to darker grey (higher elevation). The inset shows the extent of the map over Africa.