Monanthotaxis bicornis (Boutique) Verdc., Kew Bull. 25(1): 31, 1971

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 : 171-172

Monanthotaxis bicornis (Boutique) Verdc., Kew Bull. 25(1): 31, 1971

Map 6D

≡ Popowia bicornis Boutique, Bull. Jard. Bot. État Bruxelles 21: 115.

Type.

Democratic Republic of the Congo. Orientale; Yamboa, Louis J.L.P. 8957, 21 Apr 1938: lectotype, chosen by Hoekstra et al. (2021), p. 129: BR[BR0000008805386]; isolectotypes: BR[BR6102005255172, BR0000008805379]; K[K000913657]; P[P00362792] .

Description.

Liana, 30 m tall, d.b.h. unknown. Indumentum of simple hairs; old leafless branches glabrescent with lenticels, young foliate branches yellow-brown, with dense appressed yellow-brown hairs 0.2-0.4 mm long. Leaves: petiole 3-5 mm long, 0.6-1 mm in diameter, densely pubescent, cylindrical, blade inserted on the side of the petiole; blade 6-12 cm long, 1.9-3.5 cm wide, oblong to elliptic, apex acuminate, acumen 0.5-1.5 cm long, base cuneate, papyraceous, below densely pubescent when young, densely pubescent to sparsely pubescent when old, above glabrous when young and old, discolorous, whitish below; midrib impressed, above sparsely pubescent to glabrous when young and old, below densely pubescent when young and old; secondary veins 11 to 14 pairs, glabrous above; tertiary venation percurrent. Individuals bisexual; inflorescences ramiflorous on young foliate branches, axillary. Flowers with 9 perianth parts in 3 whorls, 1 to 3 per inflorescence; pedicel 15-60 mm long, 0.3-0.6 mm in diameter, sparsely pubescent to densely pubescent; basal bract ca. 1 mm long, ca. 0.5 mm wide; upper bract 0.5-1 mm long, 0.5-1 mm wide; sepals 3, valvate, free, ca. 1 mm long, 2-3 mm wide, ovate, apex acute, base truncate, densely pubescent outside, densely pubescent inside, margins flat; petals free, outer petals longer than inner; inner petals entirely covered in bud; outer petals 3, 4-6.7 mm long, 4.6-6 mm wide, ovate, apex obtuse, base truncate, yellow to white, margins flat, densely pubescent outside, pubescent with a glabrous base inside; inner petals 3, valvate, 2.5-2.8 mm long, 2.2-3 mm wide, rhombic, apex obtuse, base truncate, yellow to white, margins flat, pubescent outside, pubescent, base glabrous inside; stamens 15 to 17, in 1 row, ca. 1 mm long, oblong; connective truncate, glabrous, thecae converging apically; staminodes absent; carpels free, 6 to 9, ovary ca. 1 mm long, stigma deeply bilobed, glabrous. Fruits unknown.

Distribution.

A central African species, known from Cameroon and the Democratic Republic of the Congo; in Cameroon known from the South region.

Habitat.

A rare species only known by two collections in Cameroon, in swamp and secondary rain forests. Altitude: 100-650 m a.s.l.

Local and common names known in Cameroon.

None recorded.

Preliminary IUCN conservation status.

Endangered (EN) ( Hoekstra et al. 2021).

Uses in Cameroon.

None recorded.

Notes.

Monanthotaxis bicornis is distinguished by the branches and petioles with appressed yellow-brown hairs, the cuneate leaf base, 15 to 17 stamens in one whorl and the thecae (pollen sacs) converging apically. Converging thecae are also found in M. pellegrinii but this latter species has ascending reddish brown hairs.

Specimens examined.

South Region: Route minière E of Mt Elephant ca 20 km SE of Kribi, 2.78°N, 10.01°E, 07 April 1970, Bos J.J. 6735 (BR,K,LM,MO,P,WAG,YA); Oveng (Sangmelima), 3.09°N, 11.90°E, 22 March 1962, Breteler F.J. 2692 (B,BR,K,MO,P,U,WAG,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).