Uvariodendron kimbozaense 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 kimbozaense Dagallier & Couvreur sp. nov.

Figs 3A, C, E, G , 27 , 28

Type.

Tanzania - Morogoro • L.-P.M.J. Dagallier 49 (holotype: MPU! (MPU1379108); isotypes: DSM!, MPU! (MPU1375359), P! (P00948153); also distributed to K and WAG) ; Morogoro Rural District, Kimboza forest ; 7°01'16.37'S, 37°48'35.24'E; alt. 279 m; 15 Nov. 2019 .

Diagnosis.

Uvariodendron kimbozaense resembles Ud. kirkii by the elliptic leaves and petal colors, but is distinguished from this species by having slightly greater leaves (140-220 mm, vs. 70-190 mm long in Ud. kirkii ) with a base acute to rounded (vs. acute to decurrent). Compared to Ud. kirkii , Ud. kimbozaense also has more bracts on the flower pedicel (1 to 4, vs. 1 maximum), greater (6-12 mm long, vs. 3-6.5 mm long) and imbricate (vs. connivent) sepals, and greater (16-39 mm long, vs. 10-20 mm long), elliptic (vs. ovate), and almost flat petals (with a slight transversal curvature vs. “boat-shaped” petals, with a strong transversal curvature) (Fig. 3 , Table 2 ). Ud. kimbozaense is also distinguished from all other Uvariodendron species by the leaves having a midrib slightly raised above with a central depression all along the length of the midrib (Figs 3G , 27H ).

Description.

Tree 5-7 m tall, D.B.H. 15-20 cm; young branches sparsely pubescent to glabrous, old branches glabrous. Petiole 4-5 mm long, 1.5-2 mm wide, glabrous. Leaf lamina 147-215 mm long, 44-68 mm wide, length:width ratio 2.5-3.6, elliptic to oblong, coriaceous, base acute to rounded, apex attenuate, surface above glabrous, surface below glabrous; midrib slightly raised with a central groove all along above, raised below, glabrous above, glabrous below; secondary veins 12-17 pairs, weakly brochidodromous, impressed above, raised below; tertiary veins reticulate. Inflorescences borne on growth of the trunk and on old branches, composed of 1-11 flowers. Flower pedicel 10-14 mm long, 2-3 mm in diameter, pubescent. Flowers bisexual, buds globose to oblate, pedicellate, 5-10 mm high, 7-16 mm in diameter, pubescent. Bracts 1 at base and from 1 to 4 along the pedicel, upper bract 3-6 mm long, 6-14 mm wide, broadly ovate, adpressed, clasping the pedicel, pubescent outside, glabrous inside. Sepals 3, 6-12 mm long, 12-21 mm wide, depressed ovate, imbricate, pubescent outside, glabrous inside, green to brownish-green. Outer petals 3, 16-28 mm long, 13-19 mm wide, length:width ratio 1.2-1.8, broadly elliptic to elliptic, puberulent outside, puberulent at apex to glabrous inside, cream outside, cream with a purple-red to reddish black streak from base up to 50% of the petal length inside. Inner petals 3, 18-39 mm long, 9-18 mm wide, length:width ratio 2-2.2, obovate, slightly transversally curved, puberulent outside, glabrous inside, cream to cream with a slight purplish red streak at base outside, purple-red at base to reddish black toward the apex inside. Stamens 600 to 800, 2-3.5 mm long, 0.5-0.7 mm wide, anthers linear, connective prolongation truncate. Carpels 11 to 16, 4-5 mm long, 1.8-2 mm wide, densely pubescent, free; stigma 1-1.5 mm long, 1.5-2 mm wide, coiled, densely pubescent, covered with an exudate at anthesis. Fruits unknown.

Distribution.

Endemic to Somalia-Masai Region. Known from only one locality in Tanzania: the Kimboza Forest Reserve.

Habitat and ecology.

Lowland mature rain forest on coral rag and limestone rocks. Altitude: 250-450 m a.s.l.

Phenology.

Flowers collected in March and November.

Etymology.

The specific epithet comes from Kimboza Forest Reserve (Tanzania), from where the species is endemic.

Notes.

Ud. kimbozaense has been previously identified as Ud. kirkii in all the specimens examined. However, it clearly differs from Ud. kirkii by the characters presented in the diagnosis above (see Fig. 3 and Table 2 ). The leaves have a slightly raised midrib with a central groove all along above (Figs 3G , 27H ). It is a character unique in the genus Uvariodendron , but it is common in the genus Crematosperma ( Pirie et al. 2018). Simply raised midribs occur in other genera such as Isolona , Monodora and Ophrypetalum ( Couvreur 2009).

Preliminary conservation status.

This species is only known from the Kimboza Forest Reserve in Tanzania. This protected area has been threatened by encroachment, logging and invasion by the exotic Cedrela odorata L. ( Hall and Rodgers 1986; Patrick 2008). The surface of the Kimboza Forest Reserve is 3.85 km2 (https://www.protectedplanet.net/7520), and we thus estimate the EOO and AOO to be less than 4 km2. Following IUCN criterion B, this species is assigned a preliminary status of Critically Endangered CR B1ab(iii)+2ab(iii).

Additional specimens examined.

Tanzania - Morogoro • C.J. Kayombo 5357 (MO) ; Morogoro Rural District, Kimboza Forest Reserve ; 7°00'43'S, 37°48'50'E; alt. 400 m; 21 Mar. 2006 • T.L.P. Couvreur 71 (DSM, MO, WAG); Kilombero District, Kimboza Forest reserve, 2 km after Kimboza village , 45 km from Morogoro; 7°01'19.37'S, 37°48'16.8'E; alt. 250 m; 25 Nov. 2006 • W.R.Q. Luke 766 (EA), Uluguru Mts nr Ruvu bridge; 7°01'S, 37°49'E; alt. 450 m; 04 Nov. 1987 .

Figures

Figure 3. Morphological characters differentiating Uvariodendron kimbozaense Dagallier (A, C, E, G) and Uvariodendron kirkii Verdc. (B, D, F, H) A flowering pedicel with bracts and sepals, side view, note the imbricate sepals B flowering pedicel with bract scar and sepals C flower, with one outer petal and two inner petals gnawed, top view, note the slight transversal curvature of the inner petals D flower, top view, note the ' boat-shaped' inner petals E, F simplified representations of the flowers, from above, yellow marking highlights transversal curvature of the petals G, H Simplified representations of the transversal cut of the leaf, by the midrib. A, C Dagallier 49 (type) B, D Dagallier 23. Photos and drawings Leo-Paul Dagallier. Abbreviations: B, bract; brs bract scar; ca, carpel; ip, inner petal; lam, lamina; mlo, lower (abaxial) side of the midrib; mup, upper (adaxial) side of the midrib; op, outer petal; sep, sepal.

Figure 27. Uvariodendron kimbozaense Dagallier & Couvreur A habit B trunk with borne inflorescences C young inflorescence with flower buds D flower with one outer petal and the 3 inner petals torn or gnawed E young branch with leaves, lower side F young branch with leaves, upper side G detail of flower receptacle with stamens and stigmas, note the gleaming exudate on the stigmas and the hairs stuck on them H base of leaf, upper side, note the slightly raised midrib. A-H Dagallier 49 (type). Photos Leo-Paul Dagallier.

Figure 28. Distribution map of Uvariodendron kimbozaense. Shades of grey represent elevation, from white (sea level) to darker grey (higher elevation). The inset shows the extent of the map over Africa.