Monanthotaxis zenkeri P.H.Hoekstra, PhytoKeys 69: 98, 2016

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 : 244-246

Monanthotaxis zenkeri P.H.Hoekstra, PhytoKeys 69: 98, 2016

Fig. 73 ; Map 9G

Type.

Cameroon. South Region; Bipindi, Zenker G.A. 3495a, Oct 1907: holotype: G[G00308331]; isotypes: BR[BR0000013211349]; E[E00624356]; HBG n.v., K n.v., L[L1759466]; MO[3726267] .

Description.

Liana, height unknown, d.b.h. unknown. Indumentum of simple hairs; old leafless branches glabrous, young foliate branches densely pubescent with reddish brown, erect hairs 0.3-0.4 mm long. Leaves: petiole 3-6 mm long, 1-2 mm in diameter, densely pubescent with reddish brown erect hairs, slightly grooved, blade inserted on top of the petiole; blade 4.7-20.1 cm long, 2.3-9.5 cm wide, elliptic to obovate, apex acute to obtuse, base rounded, papyraceous to subcoriaceous, below sparsely pubescent with short erect yellow-brown hairs when young and old, above densely pubescent with erect yellow-brown hairs when young and old, discolorous, whitish below; midrib impressed, above sparsely pubescent with short erect yellow-brown hairs when young and old, below densely pubescent when young and old; secondary veins 8 to 12 pairs, glabrous above; tertiary venation percurrent. Individuals bisexual; inflorescences ramiflorous on old leafless branches, axillary. Flowers with 9 perianth parts in 3 whorls 1 to 3 per inflorescence; pedicel 4-6 mm long, 0.5-1 mm in diameter, densely pubescent; in fruit unknown; basal bract not seen; upper bract ca. 1 mm long, ca. 1 mm wide; sepals 3, valvate, basally fused, ca. 1 mm long, ca.2 mm wide, ovate to broadly triangular, apex obtuse, base truncate, densely pubescent outside, glabrous inside, margins flat; petals free, outer petals longer than inner, inner petals entirely covered in bud; outer petals 3, 2-3.1 mm long, 2.1-2.5 mm wide, ovate, apex obtuse, base truncate, margins flat, pubescent outside, pubescent towards margins to pubescent and glabrous towards center inside; inner petals 3, valvate, 1.8-2.4 mm long, 1.3-1.6 mm wide, rhombic, apex obtuse, base truncate, margins flat, densely pubescent outside, pubescent inside; stamens 35, in 3 to 4 rows, ca. 1 mm long, linear; anthers apically pubescent and converging apically and hiding the connective which is reduced or absent, glabrous; staminodes absent; carpels free, ca. 16, ovary ca. 1 mm long, stigma elongate, flattened at top, glabrous. Fruits unknown.

Distribution.

endemic to Cameroon, known from the South region.

Habitat.

Only known from the type collection, in lowland rain forests. Altitude ca. 200 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 zenkeri has unique stamens within the genus ( Hoekstra et al. 2021). It is the only species with the combination of apically pubescent anthers and a relatively short filament.

Figures

Map 9. A Monanthotaxis sterilis B Monanthotaxis submontana C Monanthotaxis tripetala D Monanthotaxis vogelii E Monanthotaxis vulcanica F Monanthotaxis whytei G Monanthotaxis zenkeri H Monodora angolensis I Monodora crispata. White borders represent region limits in Cameroon; green patches represent protected areas (see methods and Suppl. material 1: Fig. S 1).

Figure 73. Monanthotaxis zenkeri A habitus B leaf, lower side C flower bud D flower with petals removed E old flower F stamen side view G, H stamen, outer view I stamen inner side view J carpel A-J Zenker 3495 a. Drawings by Hans de Vries (Hoekstra et al. 2021, fig. 35, p. 212).