Hexalobus bussei Diels, Bot. Jahrb. Syst. 39: 479, 1907

Fig. 30; Map 4E

= Hexalobus megalophyllus Engl. & Diels, Bot. Jahrb. Syst. 39: 479, 1907. Type. Cameroon. South Region, Bipindi, Zenker G.A. 2889, 1904: holotype: B[B100154197]; isotypes: BR[BR0000015306210]; COI[COI00033178]; F; G[G00011590]; HBG[HBG518920]; K[K000198935]; L[L-0049297]; M[M0089222]; MO[MO-2246481]; P[P00315838]; S[S12-22791]; US[00098767]; WAG[WAG0053629]; WRSL; WU[WU 0025867]; Z[Z-000000827].

Type.

Cameroon. South Region; Kribi, Busse W.C.O. 3216, 1904: holotype: B[B 10 0154198].

Description.

Tree, 20-30 m tall, d.b.h. unknown; stilt roots or buttresses absent, trunk slender, not fluted. Indumentum of simple hairs; old leafless branches glabrous, young foliate branches pubescent. Leaves: petiole 1-7 mm long, 3-4 mm in diameter, pubescent, grooved, blade inserted on the side of the petiole; blade 15.5-36 cm long, 5.5-10 cm wide, obovate, apex acuminate, acumen 0.5-1 cm long, base cordate, coriaceous, below glabrous when young and old, above sparsely pubescent to glabrous when young, sparsely pubescent to glabrous when old, concolorous; midrib sunken or flat, above pubescent when young and old, below pubescent when young and old; secondary veins 12 to 17 pairs; tertiary venation reticulate. Individuals bisexual; inflorescences ramiflorous on old leafless or young foliate branches, axillary. Flowers with 9 perianth parts in 2 whorls, 1 to 2 per inflorescence; pedicel 10-12 mm long, 4-5 mm in diameter, densely pubescent; in fruit 10-13 mm long, 2-3 mm in diameter, glabrous; bracts 5 to 6, several basal and two (sometimes fused) towards the upper half of pedicel, basal bracts 3-9 mm long, 2-5 mm wide; upper bracts 6-13 mm long, 2-3 mm wide; sepals 3, valvate, free, 16-20 mm long, 11-14 mm wide, ovate, apex acute, base truncate, brown, densely pubescent outside, glabrous inside, margins flat; petals basally fused, tube 2-5 mm long, purple, inner and outer whorl not differentiated, equal, lobes 23-40 mm long, 8-10 mm wide, elliptic, apex rounded, pale yellow, margins wavy, densely pubescent outside, densely pubescent inside, plicate; stamens numerous, 7-8 mm long, elongated; connective elongated, glabrous; staminodes absent; carpels free, 3 to 7, ovary 4-5 mm long, stigma elongate, pubescent. Monocarps stipitate, ca. 1 mm long, ca. 3 mm in diameter; monocarps 2 to 4, 53-78 mm long, ca. 40 mm in diameter, ellipsoid, apex rounded, sparsely pubescent, rugose, irregularly ribbed in reticulate pattern, orange when ripe; seeds 17 to 19 per monocarp, 23-28 mm long, 17-19 mm in diameter, flattened ellipsoid; aril absent.

Distribution.

endemic to Cameroon; known from the South region.

Habitat.

A rare species, in primary lowland rain forests, sometimes riverine. Altitude 0-200 m a.s.l.

Local and common names known in Cameroon.

None recorded.

IUCN conservation status.

Endangered (EN) (Cosiaux et al. 2019l).

Uses in Cameroon.

None recorded.

Notes.

Hexalobus bussei is distinguished by its large leaf blades (15-36 cm long) and the irregularly ridged and strongly rugose surface of its monocarps.

Specimens examined.

South Region: S bank of Kienke river just E of Kribi, 3.1°N, 10.25°E, 12 May 1969, Bos J.J. 4495 (P,WAG); 21 km from Kribi high forest exploitation N of Lolodorf road, 3.03°N, 10.05°E, 07 August 1969, Bos J.J. 5157 (BR,P,WAG,YA); ca 16 km from Kribi Lolodorf road, 3°N, 10.01°E, 19 September 1969, Bos J.J. 5370 (BR,C,K,LD,LM,MO,P,WAG,YA); Kribi, 2.95°N, 9.916°E, 01 September 1904, Busse W.C.O. 3216 (B); 31 km ESE Kribi N of Kienke River Nyabessan, 2.9°N, 10.16°E, 19 April 1968, Letouzey R. 9387 (P,YA); Bipindi, 3.08°N, 10.42°E, 01 January 1904, Zenker G.A. 2889 (B,BR,COI,F,G,L,M,MO,P,S,WAG); Bipindi, 3.08°N, 10.42°E, 26 October 1908, Zenker G.A. 3550 (BR,COI,G,M,MO,P,S); Bipindi, 3.08°N, 10.41°E, 01 January 1908, Zenker G.A. 3592 (G,K); Bipindi, 3.08°N, 10.41°E, 01 January 1909, Zenker G.A. 3889 (BR,COI,G,K,L,M,MO,P,S); Bipindi, 3.08°N, 10.42°E, 01 January 1913, Zenker G.A. 4831 (BR,G,P,S).