Uvariodendron pycnophyllum (Diels) R.E.Fr., Acta Horti Berg. 10: 58 (1930)

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 pycnophyllum (Diels) R.E.Fr., Acta Horti Berg. 10: 58 (1930)

Figs 42 , 43

≡ Uvaria pycnophylla Diels, Bot. Jahrb. Syst. 53(3-5): 434 (1915). Type. Tanzania - Tanga • Brönnle 1876 (lectotype, here designated: FHO! (00060171); sheet from B lost or destroyed); Lushoto District, Amani; 5°06'S, 38°38'E; 20 Jul. 1908.

Description.

Tree 3-10 m tall, D.B.H. 20-30 cm; young branches glabrous, old branches glabrous; bark of trunk and branches reddish, external thin layers peeling off. Petiole 8-11 mm long, 1.7-3 mm wide, glabrous. Leaf lamina 158-282 mm long, 43-83 mm wide, length:width ratio 3-4.5, elliptic to oblong, coriaceous, base acute to slightly decurrent, apex attenuate to acuminate, acumen 7-13 mm long; surface above glabrous, surface below sparsely pubescent to glabrous when young, glabrous when old; midrib impressed above, raised below, glabrous above, glabrous below; secondary veins 11-17 pairs, weakly brochidodromous, impressed above, raised below; tertiary veins reticulate. Inflorescences borne on old branches or axillary, composed of 1 (sub)sessile flowers. Flower pedicel 0-10 mm long, ca. 4 mm in diameter, pubescent. Flowers bisexual, buds globose to ovoid, sessile, 7-10 mm high, 7.5-12 mm in diameter, pubescent. Bracts 2 to 6, up to 9 enclosing the bud, upper bract 10-13 mm long, 16-20 mm wide, depressed ovate to broadly ovate, adpressed, clasping the pedicel and sepals, pubescent outside, glabrous inside. Sepals 3, 10-12 mm long, ca 10 mm wide, fused at base, velutinous outside, glabrous inside, brown outside, yellow with red streak at base inside. Outer petals 3, 20-36 mm long, 16-19 mm wide, length:width ratio 1.1-2, elliptic to broadly obovate, free (valvate in bud), velutinous outside, glabrous inside, brownish to reddish-yellow outside, yellow with a pinkish-red streak from base up to 80% of the petal length inside. Inner petals 3, 20-31 mm long, ca. 15 mm wide, length:width ratio 1.9-2.1, obovate, valvate at apex (imbricate in bud), puberulent outside, glabrous inside, light yellow to cream, sometimes with a slight pinkish-red streak outside, pinkish-red to dark purplish-red with yellow margins inside. Stamens 1000 to 1200, ca. 3 mm long, ca. 0.4 mm wide, anthers linear, connective truncate, yellow. Carpels 30 to 40, 4.5 mm long, 1.2 mm wide, velutinous, free; stigma 1.5 mm long, 1.2 mm wide, coiled, velutinous, covered with an exudate at anthesis. Fruiting pedicel 0-5 mm long, 3.5 mm in diameter, velutinous. Monocarps 3 to 7, 19-35 mm long, 14-22 mm wide, length:width ratio ca 1.6-2.2, ovoid to cylindrical, pubescent, red with brown pubescence, only unripe fruits seen; sessile, stipe 0-1 mm long, 2.2 mm wide, puberulent. Seeds ca. 4 per monocarp, uniseriate, unknown.

Distribution.

Endemic to Somalia-Masai Region: Tanzania.

Habitat and ecology.

Lowland and premontane mature rain forest. Soil: rocky or sandy soil (sandstone). Altitude: 400-1025 m a.s.l.

Phenology.

Flowers collected in November. Fruits collected in April, May and November.

Notes.

This species can be differentiated from other species by its bark being reddish, with external thin layers peeling off. The specimen Brönnle 1876 in B, defined as the type by Fries (1930) was not found. We thus define the specimen Brönnle 1876 in FHO as the lectotype.

Preliminary conservation status.

A previous assessment, that needs updating, listed this species as Endangered EN under criteria B1ab(iii) (Eastern Arc Mountains & Coastal Forests CEPF Plant Assessment Project 2009c). Here the EOO of is estimated at 9,926 km2 and AOO at 32 km2. It is known from 12 occurrences in Tanzania, mostly situated in the East Usambara Mountains. Only two of the occurrences of this species are within protected areas, namely the Mtai Forest Reserve and the Kiwengoma Forest Reserve. Most of the remaining occurrences are less than 5 km from other protected areas (e.g. Amani Forest Reserve, Nilo Forest Reserve), and it is thus possible that this species occurs in these protected areas. However, this would need to be verified, and given the uncertainty of the occurrence of this species in protected areas other than Mtai and Kiwengoma Forest Reserves, the number of locations and area of occupancy is likely to decrease in the future. Following IUCN criterion B, it is thus assigned a preliminary updated conservation status of Endangered EN 2ab(ii,iv).

Additional specimens examined.

Tanzania - Lindi • C.J. Kayombo 4558 (MO); Kilwa District, T8. NE end of Mbarawala Plateau, above valley running SE. Evergreen mixed dry rocky forest. Transect #3; 9°00'47'S, 39°07'59'E; alt. 280 m; 04 Nov. 2003 - Pwani - Frontier-Tanzania Coastal Forest Res.Prog 700 (K, MO); Rufiji District, Kiwengoma Forest. Northern edge of the Matumbi Highlands ; 8°21'S, 38°56'E; alt. 365 m; 31 Jan. 1990 - Tanga • D.M. Johnson 1947 (DSM); Muheza District, along road Bombani-Kisiwani, ca 3 km from Kisiwani ; 5°01'S, 38°38'24'E; alt. 400 m; 05 Jun. 1996 • F.M. Mbago 3366 (DSM); Muheza District, 3 km from Kisiwani to Bombani along the road; 5°06'38.38'S, 38°40'49.08'E; alt. 150 m; 18 May. 2005 • L.-P.M.J. Dagallier 33 (BR, DSM, K, MO, MPU, P, WAG); Muheza District, along the road to Amani Nature Reserve ; 5°06'04.38'S, 38°40'30.44'E; alt. 359 m; 11 Nov. 2019 • L.-P.M.J. Dagallier 37 (DSM, K, MO, MPU, P, WAG); Muheza District, along the road to Amani Nature Reserve ; 5°06'07.38'S, 38°40'16.12'E; alt. 378 m; 12 Nov. 2019 • L.B. Mwasumbi 112474 (DSM); Muheza District, T3: Kwamngumi Forest Reserve ; 4°57'S, 38°43'E; 12 Mar. 1999 - Langheinrich FHDS2889 (B); Korogwe District, W Usambara Mts., Bungu ; 5°03'S, 38°24'E; Jul. 1912 • M.A. Mwangoka 26 (MO); Korogwe District, (T3) West Usambara Mountains, riverine forest patch in Kieti Village ; 5°03'21'S, 38°24'17'E; alt. 1025 m; 31 May. 2002 • M.A. Mwangoka 6168 (MO); Muheza District, East Usambaras mountains, Kiwanda village Forest ( Mpangamanyoka forest ). W part of the forest; 5°02'32'S, 38°43'38'E; alt. 310 m; 05 Apr. 2009 • T.L.P. Couvreur 21 (DSM, K, MO, WAG); Muheza District, on road 200 m before arriving to Kisiwani village ; 5°06'28.8'S, 38°40'55.2"E; alt. 300 m; 12 Nov. 2006 .

Figures

Figure 42. Uvariodendron pycnophyllum (Diels) R. E. Fr. A trunk, note the reddish peeling bark B young branch with leaves, upper side C young branch with leaves, lower side D young flower, top view E semi-open flower, top view F fruit, side view. A Dagallier 33 B, D-F Couvreur 21 C Dagallier 37. Photos A, C Leo-Paul Dagallier B, D-F Thomas Couvreur.

Figure 43. Distribution map of Uvariodendron pycnophyllum. Shades of grey represent elevation, from white (sea level) to darker grey (higher elevation). The inset shows the extent of the map over Africa.