Monanthotaxis couvreurii P.H.Hoekstra, PhytoKeys 69: 79, 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 : 182-184

Monanthotaxis couvreurii P.H.Hoekstra, PhytoKeys 69: 79, 2016

Fig. 51 ; Map 6I

Type.

Cameroon. Central Region ; Ottotomo Forest Reserve, Couvreur T.L.P. 762, 24 Apr 2015: holotype: WAG[WAG.1576998, WAG.1576999, WAG.1577000]; isotypes: MPU[MPU1374962]; YA n.v .

Description.

Liana, up to 20 m tall, d.b.h. up to 4 cm. Indumentum of simple hairs; old leafless branches glabrous, young foliate branches densely pubescent with dense ascending reddish brown 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 4.5-12 cm long, 1.5-4.5 cm wide, oblong to obovate, apex acuminate to acute, acumen ca. 1 cm long, base cuneate to rounded, papyraceous, below sparsely pubescent when young and old, above sparsely pubescent when young, glabrous when old, discolorous, whitish below; midrib sunken or flat, above glabrous when young and old, below pubescent when young and old; secondary veins 7 to 11 pairs, glabrous above; tertiary venation percurrent. Individuals bisexual; inflorescences cauliflorous or more rarely ramiflorous on old leafless branches, axillary. Flowers with 9 perianth parts in 3 whorls, 1 to 2(3) per inflorescence when on branches, up to 20 per inflorescence when on main trunk; pedicel 4-20 mm long, ca. 1 mm in diameter, sparsely pubescent; in fruit unknown; basal bract not seen, upper bract minute, ca. 0.5 mm, ca. 1 mm wide; sepals 3, valvate, basally fused, ca. 1 mm long, 1 mm wide, triangular, apex acute, base truncate, brown, densely pubescent outside, glabrous inside, margins flat; petals free, subequal, inner petals partly covered in bud; outer petals 3, 3.5-5 mm long, 2-3.5 mm wide, elliptic to ovate, apex obtuse, base truncate, light yellow to white, margins flat, densely pubescent outside, sparsely pubescent inside; inner petals 3, valvate, 3-4.5 mm long, 1.2-1.5 mm wide, elliptic to ovate, apex acute, base truncate, light yellow to white, margins flat, pubescent outside, glabrous inside; stamens 13 to 15, in 1 row, basally fused between each them, ca. 1 mm long, linear; connective truncate to rounded, pubescent, cream; staminodes absent; carpels free, 9 to 12, ovary ca. 1 mm long, stigma globose, glabrous. Fruits unknown.

Distribution.

endemic to Cameroon; known from the Central Region.

Habitat.

A rare species, in lowland old secondary rain forests. Attitude around 700 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 recorded.

Notes.

Monanthotaxis couvreurii is distinguished by its mainly cauliflorous flowers (but may also be ramiflorous) and its stamens in one row that are basally fused, a unique feature in Monanthotaxis ( Hoekstra et al. 2016). This species is only known from the Ottotomo Forest reserve, near Yaoundé.

Specimens examined.

Central Region: Ottotomo Forest Reserve 45 km South of Yaoundé ca 5 km on main path into reserve, 3.65°N, 11.28°E, 24 April 2015, Couvreur T.L.P. 762 (WAG,YA); Reserve Forestière d’Ottotomo 40 km de Yaoundé sur la route de Kribi, 3.64°N, 11.27°E, 05 May 1970, Farron C. 7266 (P); Reserve forestière d’Ottotomo Yaoundé à environ 40 km au SW sur la route de Makak, 3.64°N, 11.27°E, 26 May 1970, Farron C. 7359 (YA) .

Figures

Map 6. A Letestudoxa lanuginosa B Meiocarpidium oliverianum C Mischogyne gabonensis D Monanthotaxis bicornis E Monanthotaxis bokoli F Monanthotaxis capea G Monanthotaxis cauliflora H Monanthotaxis congoensis I Monanthotaxis couvreurii. White borders represent region limits in Cameroon; green patches represent protected areas (see methods and Suppl. material 1: Fig. S 1).

Figure 51. Monanthotaxis couvreurii A habit, liana growing on tree B leaves, upper side C base of leaf blade, lower side D cauliflorous inflorescence, one flower opened E cauliflorous inflorescence, side view F detail of flower top view, note the 15 stamens fused at their base forming a ring around the carpels in the center A-F Couvreur 762, Ottotomo, Cameroon. Photos Thomas L. P. Couvreur.