Uvariodendron fuscum (Benth.) R.E.Fr., Acta Horti Berg. 10: 61, 1930

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 : 393-395

Uvariodendron fuscum (Benth.) R.E.Fr., Acta Horti Berg. 10: 61, 1930

Fig. 122 ; Map 15E

≡ Uvaria fusca Benth., Trans. Linn. Soc. London 23(3): 466, 1862; Uva fusca (Benth.) Kuntze, Revis. Gen. Pl. 1: 8, 1891.

= Uvariodendron mirabile R.E.Fr., Acta Horti Berg. 10: 59, 1930 (including Uvaria connivens Engl. & Diels, Monogr. Afr. Plf. VI: 12, 1901, pro parte specimens Lehmbach 57 and 178). Syn. nov. Type. Cameroon. South Region; between Victoria and Bimba, Preuss C.G.T. 1378, 15 Mar 1898: lectotype, here designated: P[P00315830] (B destroyed ( Le Thomas 1969b)).

Type.

Type. Equatorial Guinea. Bioko Norte; Bioko (Fernando Po), Mann G. 308, 1860: holotype: K[K000198801]; isotype: P[P00362657] .

Description.

Tree, 3-15 (20) m tall, up to 35 cm d.b.h.; stilt roots or buttresses absent. Indumentum of simple hairs; old leafless branches glabrous, young foliate branches glabrous to slightly pubescent. Leaves: petiole 4-35 mm long, 2-8 mm in diameter, glabrous to pubescent with long white hairs, slightly grooved, blade inserted on top of the petiole; blade 15.9-70 cm long, 4.3-22.5 cm wide, narrowly elliptic to elliptic to narrowly obovate to obovate, apex acuminate, acumen 0.4-1.5 cm long, base rounded to acute (sometimes slightly truncate), coriaceous, below densely pubescent with long white hairs to glabrous when young, glabrous when old, above glabrous when young and old; midrib sunken or flat, above glabrous when young and old, below glabrous when young, glabrous to slightly pubescent when old; secondary veins 15 to 33 per side, glabrous above; tertiary venation reticulate. Individuals bisexual; inflorescences cauliflorous or ramiflorous on old or young foliate branches, axillary. Flowers with 9 perianth parts in 3 whorls, 1 to 3 per inflorescence; pedicel 0-7.5 mm long, ca. 4 mm in diameter, pubescent; in fruit 9-15 mm long, 7-8 mm in diameter, densely pubescent; bracts 2 to 6, basal bracts 2-3 mm long, 1-3 mm wide; upper bracts 8-22 mm long, 10-50 mm wide; sepals 3, valvate, basally fused over 20-50% of the length, 11-30 mm long, 13-26 mm wide, ovate, apex acuminate, base truncate, densely pubescent outside, glabrous inside, margins flat; petals free, sub equal; outer petals 3, 20-40 mm long, 17-30 mm wide, ovate, apex acuminate, base truncate, margins flat, densely pubescent outside, glabrous inside, cream with a red streak inside; inner petals 3, valvate, 20-42 mm long, 15-29 mm wide, ovate, apex acuminate, base truncate, margins flat, pubescent outside, glabrous inside, cream with a red streak inside; stamens 1000 to 3000, in 19 to 25 rows, 3.4-5 mm long, 0.1-0.5 mm wide, linear; connective discoid, pubescent; staminodes absent; carpels free, 20 to 104, ovary 4-7 mm long, stigma bilobed, slightly capitate, densely pubescent. Monocarps [but see comment in notes] sessile to stipitate, stipes 0-4 mm long, 2-5 mm in diameter; monocarps 6 to 24, 20-50 mm long, 11-25 mm in diameter, obovoid to oblong, apex rounded or shortly narrowed, pubescent, smooth; seeds 6 to 16 per monocarp, 10-15 mm long, 6-11 mm in diameter, flattened ellipsoid; aril absent.

Distribution.

Nigeria, Cameroon, Equatorial Guinea; in Cameroon known from the South-West region.

Habitat.

A common species; mainly in lowland to premontane to mountain primary or old secondary rain forests. Altitude 100-1400 m a.s.l.

Local and common names known in Cameroon.

Obom, ossoé ( Yaoundé, Biholong 279), Limboto (Bakweri, van Andel 3761).

IUCN conservation status.

Not evaluated yet as taxonomically defined here. Cheek and Cable (2000) assessed U. fuscum as Near Threatened (NT), but this didn’t follow the taxonomic concept assigned here (including U. mirabile ). Likely Least Concern (LC).

Uses in Cameroon.

None reported.

Notes.

Uvariodendron fuscum resembles U. molundense but has larger sepals that are fused (11-55 mm long vs. imbricate and 5-10 mm long). It also resembles U. calophyllum and U. connivens but differs in having pilose to glabrous young branches and petioles (vs. tomentose in U. calophyllum and completely glabrous in U. connivens ). Additionally, it differs from U. connivens in having flowering pedicels 0-7.5 mm long (vs. 10-40 mm long) and in having cream petals with dark red streak within the flower (vs. wine red petals both inside and outside).

The description of the fruits are based on specimens assigned to var. Uvariodendron connivens giganteum (see below). Only young immature fruits were seen might be apparent between both varieties with better fruiting material.

We synonymize here the name U. mirabile ( Le Thomas 1967a) with U. fuscum . The study of the type specimens together with other specimens led us to consider them as conspecific. The only remaining collection of Preuss 1378 found in P (the holotype of U. mirabile as defined by Fries 1930 was destroyed in Berlin) has small leaves that appear different from the longer leaves of Mann 308 (the holotype of U. fuscum as defined by Fries 1930). However, the specimen Wieringa 2058 presents both types of leaves, as well as leaves of intermediate size, revealing that this character is quite variable within the species. The name Uvariodendron occidentalis Le Thomas ( Le Thomas 1967a) however is retained as a good species, but absent from Cameroon to date (a west African species).

We also recombine the name U. giganteum in U. fuscum as a new variety: var. Uvariodendron fuscum giganteum . Both varieties have elliptic to obovate leaves, sepals which are fused at base over up to half of their length, free and ovate outer petals, and free and obovate inner petals. They differ, however, by the size of their leaves (lamina length, number of secondary veins) and the size of their flowers (sepals and petals dimensions, number of carpels) -see key to varieties below. However, these characters overlap along a continuum, with U. fuscum var. fuscum having smaller dimensions than U. fuscum var. giganteum and some of the specimens we examined were hard to place in one or the other variety (e.g. Couvreur 1029).

Specimens examined.

South-West Region: Likombe , 4.11°N, 9.183°E, 22 February 1995, Cable S. 1353 (K,YA); Upper Boando , 4.06°N, 9.15°E, 14 March 1995, Cable S. 1524 (K,YA); Upper Boando , 4.06°N, 9.15°E, 16 March 1995, Cable S. 1626 (K,YA); Ekundu Kundu, 5.14°N, 8.893°E, 26 April 1996, Cable S. 2187 (K,WAG,YA); Liwenyi, 4.37°N, 9.013°E, 27 October 1993, Cheek M. 5145 (K,YA); on trail leading to top of Mt Etinde after Ekonjo village , 4.06°N, 9.152°E, 01 April 2016, Couvreur T.L.P. 1026 (WAG,YA); on trail leading to top of Mt Etinde after Ekonjo village , 4.06°N, 9.153°E, 01 April 2016, Couvreur T.L.P. 1029 (WAG,YA); Mount Cameroon National Park Bakinguili trail above Bakinguili village , 4.09°N, 9.056°E, 02 April 2016, Couvreur T.L.P. 1040 (WAG,YA); Mount Cameroon National Park on the Bomona trail behind Bomona village 10 km NW from Idenau, 4.29°N, 9.101°E, 03 April 2016, Couvreur T.L.P. 1046 (WAG,YA); slopes of Mount Cameroon on the Bokwango trail near Bokwango village 4 km south west of Bu 4.12°N, 9.186°E, 23 March 2016, Couvreur T.L.P. 990 (WAG,YA); slopes of Mount Cameroon on the Bokwango trail near Bokwango village 4 km south west of Bu 4.12°N, 9.170°E, 23 March 2016, Couvreur T.L.P. 992 (WAG,YA); Likombe, 4.11°N, 9.183°E, 02 March 1995, Dahl A. 622 (K,YA); Likombe, 4.11°N, 9.183°E, 21 February 1995, Groves M. 122 (K,YA); Kumba Distr eastern boundary of Bambuko FR ca 11 miles SSW of Musome, 4.33°N, 9.166°E, 01 February 1958, Keay R.W.J. 37485 (K); on Shrike Trail leading from Nyasoso to summit, 4.83°N, 9.666°E, 20 June 1994, Lane P. 142 (K,YA); Bu 4.15°N, 9.233°E, 1898, Lehmbach H. 178 (B,K); Bu 4.15°N, 9.233°E, 1898, Lehmbach H. 57 (B,K); Buea above upper farms, 4.15°N, 9.233°E, 01 March 1929, Maitland T.D. 453 (K); Cameroon Mountain Buea area 4.15°N, 9.233°E, 01 January 1930, Maitland T.D. s.n. (K[K000105371]); Likomba-Pflanzung 15-35 km NE von Victoria [Limbe], 4.1°N, 9.333°E, 01 November 1928, Mildbraed G.W.J. 10720 (K); Mt Cameroun flanc d’Ekona Lelu, 4.27°N, 9.3°E, 14 January 1985, Nkongmeneck B.A. 891 (YA); Between Limbe & Bimbia , 3.96°N, 9.25°E, 1895, Preuss P.R. 1378 (P); Mount above small Koto village, 4.3°N, 9.1°E, 06 March 1985, Thomas D.W. 4469 (K,MO,P,YA); Etinde Mont, 4.08°N, 9.116°E, 29 January 1994, Wieringa J.J. 2058 (WAG) .

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 122. Uvariodendron fuscum var. fuscum A leaf B base of leaf blade, upper side side C base of leaf blade, lower side D cauliflorous flowers E detail of flower F detail of flower G flower, bottom view, showing bracts and sepals, note fused sepal base H detail of outer petal and a beetle covered in pollen I young fruit with an old petal A-C Couvreur 1040, Mt Cameroon, Cameroon D-F Couvreur 1029; Mt Cameroon, Cameroon G-I Couvreur 1046, Mt Cameroon, Cameroon. Photos Thomas L. P. Couvreur.