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

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 : 209-212

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.

Figures

Map 8. A Monanthotaxis hexamera B Monanthotaxis hirsuta C Monanthotaxis klainei D Monanthotaxis laurentii E Monanthotaxis letouzeyi F Monanthotaxis montana G Monanthotaxis paniculata H Monanthotaxis pellegrinii I Monanthotaxis pynaertii. White borders represent region limits in Cameroon; green patches represent protected areas (see methods and Suppl. material 1: Fig. S 1).

Figure 60. Monanthotaxis hexamera A flowering branch B flower C outer petal, inner view D outer petal, outer view E outer petal, outer detail F inner petal, outer view G inner petal, inner view H stamen, back view I stamen, side view J stamen, front view K carpel, side view L carpel, front view A-L from Letouzey 10288. Drawing by Hans de Vries (Hoekstra et al. 2021, fig. 16, p. 164).