Monanthotaxis hexamera P.H.Hoekstra, Blumea 66 (1): 163, 2021

Fig. 60; Map 8A

Type.

Cameroon. South Region; près de zingui, Letouzey R.G. 10288, 5 Apr 1970: holotype: P[P01960096]; isotype: YA[YA0002998] .

Description.

Liana, up to 3 m tall, d.b.h. unknown. Indumentum of simple hairs; old leafless branches glabrescent, young foliate branches pubescent with dense appressed to ascending yellowish-white hairs 0.1-0.2 mm long. Leaves: petiole 3-5 mm long, ca. 1 mm in diameter, densely pubescent, slightly grooved, blade inserted on top of the petiole; blade 9.5-11.5 cm long, 3.3-4.1 cm wide, oblong to elliptic, apex acute, acumen 0.5-1 cm long, base rounded to subcordate, papyraceous, below sparsely pubescent with yellowish-white hairs when young and old, above glabrous when young and old, discolorous, whitish below; midrib impressed, above glabrous when young and old, below pubescent when young, sparsely pubescent when old; secondary veins 11 to 13 pairs, glabrous above; tertiary venation percurrent. Individuals bisexual; inflorescences ramiflorous on old leafless branches, leaf opposed to axillary. Flowers with 9 perianth parts in 3 whorls, 1 to 4 per inflorescence; pedicel 15-24 mm long, ca. 0.5 mm in diameter, sparsely pubescent; in fruit unknown; bracts 2, one basal and one upper towards the lower half of pedicel, basal bract ca. 1 mm long, ca. 0.5 mm wide; upper bract ca. 1 mm long, ca. 0.5-1 mm wide; sepals 3, valvate, basally fused, ca. 1 mm long, ca. 1 mm wide, ovate, apex acute, base truncate, sparsely pubescent outside, glabrous inside, margins flat; petals free, outer petals longer than inner, inner petals entirely covered in bud; outer petals 3, 4.5-8 mm long, 3.7-5.8 mm wide, ovate, apex rounded to obtuse, base truncate, white, margins flat, sparsely pubescent outside, pubescent, base glabrous inside; inner petals 3, valvate, ca. 5.1 mm long, 2.7-2.9 mm wide, elliptic, apex obtuse and shortly acuminate, base truncate, margins flat, densely pubescent outside, pubescent with a glabrous base inside; stamens 6, in 1 row, ca. 2 mm long, linear; connective truncate, pubescent, filament ca. 2 mm long; staminodes absent; carpels free, 6, ovary ca. 2 mm long, stigma globose, glabrous. Fruits unknown.

Distribution.

endemic to Cameroon; known only from the type locality in the South region.

Habitat.

In bushy scrub. Altitude ca. 450 m a.s.l.

Local and common names known in Cameroon.

None recorded.

Preliminary IUCN conservation status.

Critically Endangered (CR) (Hoekstra et al. 2021).

Uses in Cameroon.

None reported.

Notes.

Monanthotaxis hexamera can be distinguished from the other Cameroonian species by the yellowish-white hairs on the branches and leaf underside. Furthermore, the stamens have very long filaments (ca. 2 mm long versus less than 0.5 mm long in other species), a characteristic only shared with Monanthotaxis filamentosa, which has a very different indumentum consisting of long erect reddish-brown hairs.