Evergreen tree of up to 40 m tall; trunk up to 1 m dbh, deeply channelled (giving it the appearance of a bundle of columns); bark c. 5 mm thick, longitudinally fissured, peeling off in narrow, long papery flakes, brown to rusty-brown, quickly turning orange-brown when cut; twigs, leaves and petioles densely hairy when young. Leaves: petiole 2-8 mm long, 1-2.5 mm in diam., covered with brown to whitish hairs; leaf blade elliptic to ovate or obovate, 7.2-25 cm long, 2.5-8.5 cm wide, apex acuminate with a blunt tip, base cordate to rounded or sometimes cuneate, coriaceous; upper surface sometimes slightly bullate, glossy, often greyish, glabrous, lower surface brown when dry, sparsely covered with appressed, light brown hairs of c. 0.3 mm long; midrib covered with small, erect, white hairs above, below covered with appressed, light brown hairs; secondary veins distinct on each side, 9-19 pairs, at angles of 42-75º with the midrib. Flowers 1-3 together on simple or branched short shoots, fragrant; flower stalk 12-25 mm long; the part of the flower stalk below the articulation 2-13 mm long, 1-2 mm in diam., in fruit 4-9 mm in diam.; bracts 5-6, two upper ones barely to distinctly fused at base and then forming a tube to 4 mm long, soon falling except when fused, 8-12 mm long, 4-9 mm wide; part of the flower stalk above the articulation 4-17 mm long, 1.2-3 mm in diam., in fruit 4-10 mm in diam., densely covered with appressed, golden to rusty-brown, c. 0.5 mm long hairs; buds ovoid to more or less globose; sepals 12-16 (-21) mm long, (5.5-) 9-12 (-16) mm wide, reflexed at anthesis, outside densely covered with < 0.1 mm, appressed, rusty-brown hairs and with larger, (0.5-) 0.8-1.5 (-2) mm long hairs, inside densely covered with curly hairs; corolla cream to yellow, basal rim dark purple, tube 4-10 mm long, lobes narrowly to broadly lanceolate, all equal or sometimes subequal with those of the inner whorl narrower, 37-60 (-80) mm long, 6-21 mm wide, rounded at apex, outside with appressed, light coloured to brown, 0.1-1 mm long hairs, apical hairs shorter than basal ones; inside covered with appressed, c. 0.1 mm long hairs, base glabrous or sparsely covered with curly, fine, white, long hairs; stamens numerous, oblong or sometimes slightly broadening towards apex, 3-5.1 mm long, 0.5-0.8 mm wide, connective appendage semi-globose to slightly convex; carpels 7-16, 2-4.5 mm long, 1-1.3 mm wide, densely hairy; stigmas attached to the top of the ovary, often bending in a horizontal position, 2.1-3.5 mm long, (1.1-) 2.2-3.1 mm wide. Monocarps 1-5 (-8), subsessile, ellipsoid to oblong, (4.2-) 5-9.5 cm long, 3.5-6.5 cm in diam., smooth, glabrous or densely covered with velutinous, rusty-brown, c. 0.1 mm hairs; seeds c. 12-36, biseriate, flattened ellipsoid with convex or plano-convex sides, 28-40 mm long, 17-20 mm wide, 5-9 mm thick, rusty-brown to dark brown, dull to slightly shiny, raphe flat, slightly darker brown.
Hexalobus crispiflorus is morphological very close to H. salicifolius, both being large trees with deeply channelled trunks, similar floral morphology and occurring in similar habitats. This has lead to some different views on the taxonomic status of both species (e.g. considered as two subspecies, Wilks et al. 2000). However, we consider them here as two distinct species, in agreement with Le Thomas (1969). Hexalobus crispiflorus can be distinguished by its generally larger leaf blades, larger number of carpels (7-16) and especially by its smooth monocarp surface, in contrast to the verrucose surface of those in H. salicifolius. To a lesser extent, H. crispiflorus resembles H. bussei. The latter can, however, be easily distinguished by its rugose monocarp surface as well as its much larger leaves and longer oblong stamens.
Least Concern. Hexalobus crispiflorus is widely distributed across Africa, and has been collected numerous times. Moreover, it has been collected in several protected areas such as national parks (la Marahoue (Ivory Coast), Doudou Mountains, Loango and Lopé Reserve (Gabon), Manovo-Gounda St Floris (Central African Republic), Odzala (Republic of the Congo), la Garamba (Democratic Republic of the Congo)) and reserves (Ohosu, Pénéssoulou (Benin), Jimira and Tano Ofin (Ghana), Aponmu, Akure and Ibaji-Ojoko (Nigeria)). Therefore the “least concern” category is applied.
From Guinea to the southern part of Sudan, and south to the northern province “Lunda Norte” in Angola and to the south of Democratic Republic of the Congo.
A species from tropical rain forests and gallery forests, sometimes growing in woodland savannas, often near water or in temporarily inundated forests, from sea level to 1000 m altitude.