Hexalobus monopetalus (A. Rich.) Engl. & Diels, Monogr. Afrik. Pflanzen.-Fam. 6: 56, 1901

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 : 126-127

Hexalobus monopetalus (A. Rich.) Engl. & Diels, Monogr. Afrik. Pflanzen.-Fam. 6: 56, 1901

Fig. 30 ; Map 4G

≡ Uvaria monopetala A.Rich., Guill. & Perr., Fl. Seneg. tent.: 8, 1831. Hexalobus senegalensis A.DC., Mém. Soc. Phys. Genève 5: 213, 1832, superfluous name.

= Hexalobus monopetalus var. parvifolius Baker.f.; Macleod, Chiefs and cities of Central Africa: 301, 1912. Type. Central African Republic. Environs de Kaga M’bra, Chevalier A.J.B. 6486, 30 Nov 1902: holotype: K[K000582056]; isotypes: G[G00011614]; L[L0049298]; P; WAG[WAG0162940].

= Hexalobus tomentosus A.Chev., Expl. bot. Afr. occ. Énum. pl. 1: 10, 1920. Type. Mali. Ségou, Sansanding, Chevalier A.J.B. 2542, 29 Sep 1899: lectotype, designated by Botermans et al. (2011), p. 42: P[P00486157].

= Hexalobus glabrescens Hutch. & Dalziel, Fl. W. trop. Afr. 1: 52, 1927. Type. Central African Republic: Ouham, Lere to Ham, Talbot P.A. 531, 1911: lectotype, designated by Botermans et al. (2011), p. 42: K; isolectotypes: BM[BM000546380]; Z[Z-000034501].

= Hexalobus monopetalus (A. Rich.) Engl. & Diels var. obovatus Brenan, Mem. New York Bot. Gard. 8, 3: 214, 1953. Type. Zambia. North-Western, E. of Matonchi Farm, Milne-Redhead E.W.B.H. 4536, 12 Feb 1938: holotype: K[K000198933]; isotypes: BM[BM000546381]; BR[BR0000008800664]; PRE[PRE0397001-0].

= Hexalobus huillensis (Engl. & Diels) Engl. & Diels, Monogr. Afrik. Pflanzen.-Fam. 6: 56, 1901; Uvaria huillensis Engl. & Diels, Notizbl. Königl. Bot. Gart. Berlin. 2: 296, 1899. Type. Angola. Benguela, Benguella, Huilla, Antunes J.M. 266, no date: lectotype, designated by Botermans et al. (2011), p. 42: COI[COI00033141]; isolectotype: BM[BM000546379].

Type.

Senegal. Tambacounda; Galam prope Bakel, Leprieur F.M.R. s.n., 1828: lectotype, designated by Botermans et al. (2011), p. 42: G[G00011597]; isolectotypes: G[G00011595, G00011593]; P[P00315834, P00315832, P00315836] .

Description.

Tree to shrub, 10-15 m tall, d.b.h. up to 35 cm; stilt roots or buttresses absent, often several stemmed, not fluted. Indumentum of simple hairs; old leafless branches glabrous, young foliate branches pubescent. Leaves: petiole 1-4 mm long, 1-2 mm in diameter, densely pubescent, grooved, blade inserted on the side of the petiole; blade 3.6-17.5 cm long, 1.2-6.5 cm wide, ovate to obovate, apex rounded to obtuse, rarely acuminate, acumen 1 cm long, base cuneate to cordate, coriaceous, below pubescent when young, glabrous when old, above pubescent when young, glabrous when old, concolorous; midrib impressed, above pubescent when young, glabrous when old, below pubescent when young, glabrous when old; secondary veins 6 to 14 pairs, below; tertiary venation reticulate. Individuals bisexual; inflorescences ramiflorous on young foliate branches, more rarely cauliflorous, axillary. Flowers with 9 perianth parts in 2 whorls, 1 to 3 per inflorescence; pedicel sessile or short up to 2 mm long, ca. 2 mm in diameter when present, densely pubescent; in fruit 2-4 mm long, 1-2 mm in diameter, sparsely pubescent; bracts 5 to 6, several basal and two (sometimes fused) towards the upper half of pedicel, basal bracts ca. 5 mm long, ca. 4 mm wide; upper bracts ca. 5 mm long, ca. 4 mm wide; sepals 3, valvate, free, 4-7 mm long, 3-6 mm wide, ovate, apex acute, base truncate, brown, densely pubescent outside, glabrous inside, margins flat; petals basally fused, tube 3-4 mm long, inner and outer whorl not differentiated, sub equal; lobes 9-27 mm long, 3-7 mm wide, elliptic, apex rounded, cream, margins wavy, pubescent outside, pubescent inside, lobes curving inwards at the base and margins reflexed forming a hollow chamber; stamens numerous, 1-2 mm long, elongated; connective discoid, glabrous, cream-yellow; staminodes absent; carpels free, 2 to 7, ovary 2-3 mm long, stigma divided into two lobes with margins coiled inwards, pubescent. Monocarps stipitate to sessile, stipes <3 mm long, 3-4 mm in diameter; monocarps1 to 5, 22-46 mm long, 13-22 mm in diameter, ellipsoid to cylindrical, apex rounded, sparsely pubescent, warty, constricted around the seeds, orange when ripe; seeds 2 to 8 per monocarp, 10-15 mm long, 7-10 mm in diameter, flattened ellipsoid; aril absent.

Distribution.

A widespread species, known from Senegal to northern South Africa, with a disjunct population in southern Angola; in Cameroon known from the North and Far-North regions.

Habitat.

A common species in drier regions of Africa; in woodland, savannas or gallery forests, on sandy soils or in rocky places. Altitude 200-1000 m a.s.l.

Local and common names known in Cameroon.

Bohili ( Fulfuldé) ( Malzy 1954).

IUCN conservation status.

Least Concern (LC) ( Cosiaux et al. 2019n).

Uses in Cameroon.

None recorded.

Notes.

Hexalobus monopetalus is distinguished from the other Cameroonian species by being a small deciduous shrub or tree (no taller than 15 m) growing in drier areas, with sessile or subsessile flowers and small smooth monocarps (up to 46 mm long versus more than 45 mm generally).

Selected specimens examined.

Far-North Region: Route Lara-Guidiguis (15 km ENE de Kaele), 10.1°N, 14.45°E, 29 August 1964, Letouzey R. 6540 (P,YA); Près Bourka (65 km SS0 de Mokolo), 10.3°N, 13.56°E, 13 October 1964, Letouzey R. 7301 (P,YA); 9 km SE Guili 10 km NE Bourrah, 10.6°N, 13.74°E, 27 November 1989, Villiers J.-F. 4713 (P,YA). North Region : Ecole de faune de Garoua , 9.3°N, 13.4°E, 09 August 2000, Dong E. 393 (YA); Sanguéré (10 km Garoua), 9.27°N, 13.47°E, 01 October 1949, Malzy P. 309 (P,YA); Environs village Boulko au pied Hossere Gode 15 km NW de Poli, 8.53°N, 13.13°E, 24 October 1983, Satabié B. 702 (P,YA); Collines de Tinguelin 10 km N de Garoua, 9.3°N, 13.4°E, 26 November 1984, Satabié B. 781 (P,YA); map # NC 33 VIII Garoua, 9.93°N, 13.86°E, 13 August 1983, Thomas D.W. 2432 (MO,P,WAG,YA) .

Figures

Map 4. A Duguetia dilabens B Duguetia staudtii C Greenwayodendron glabrum D Greenwayodendron suaveolens E Hexalobus bussei F Hexalobus crispiflorus G Hexalobus monopetalus H Hexalobus salicifolius I Isolona campanulata. White borders represent region limits in Cameroon; green patches represent protected areas (see methods and Suppl. material 1: Fig. S 1).

Figure 30. Hexalobus bussei A flowering branch B stamen, front view. Hexalobus monopetalus C flowering branch D opened flower, one sepal and one petal removed E stamen, front view F portion of pedicel with three monocarps A, B from Zenker 3550 C-E from Letouzey 7301 F from Chevalier 305. Drawings by Helene Lamourdedieu, Publications Scientifiques du Museum national d'Histoire naturelle, Paris; modified from Botermans et al. (2011, fig. 3, p. 35).