Flora of Cameroon - Annonaceae Vol 45 Author Couvreur, Thomas L. P. https://orcid.org/0000-0002-8509-6587 IRD, DIADE, Univ Montpellier, Montpellier, France & Universite de Yaounde I, Ecole Normale Superieure, Departement des Sciences Biologiques, Laboratoire de Botanique systematique et d'Ecologie, B. P. 047, Yaounde, Cameroon & Naturalis Biodiversity Center, Botany Section, Darwinweg 2, 2333 CR Leiden, Netherlands thomas.couvreur@ird.fr Author Dagallier, Leo-Paul M. J. https://orcid.org/0000-0002-3270-1544 IRD, DIADE, Univ Montpellier, Montpellier, France Author Crozier, Francoise IRD, DIADE, Univ Montpellier, Montpellier, France Author Ghogue, Jean-Paul Universite de Yaounde I, Ecole Normale Superieure, Departement des Sciences Biologiques, Laboratoire de Botanique systematique et d'Ecologie, B. P. 047, Yaounde, Cameroon & Green Connexion, Environmental Group, siege face GP Melen, a cote de l'immeuble Palais des verres. Yaounde, Cameroun Author Hoekstra, Paul H. Naturalis Biodiversity Center, Botany Section, Darwinweg 2, 2333 CR Leiden, Netherlands Author Kamdem, Narcisse G. Universite de Yaounde I, Ecole Normale Superieure, Departement des Sciences Biologiques, Laboratoire de Botanique systematique et d'Ecologie, B. P. 047, Yaounde, Cameroon Author Johnson, David M. https://orcid.org/0000-0003-2896-7419 Department of Botany-Microbiology, Ohio Wesleyan University, Delaware, OH, 43015, USA Author Murray, Nancy A. Department of Botany-Microbiology, Ohio Wesleyan University, Delaware, OH, 43015, USA Author Sonke, Bonaventure https://orcid.org/0000-0002-4310-3603 Universite de Yaounde I, Ecole Normale Superieure, Departement des Sciences Biologiques, Laboratoire de Botanique systematique et d'Ecologie, B. P. 047, Yaounde, Cameroon text PhytoKeys 2022 2022-09-20 207 1 532 http://dx.doi.org/10.3897/phytokeys.207.61432 journal article http://dx.doi.org/10.3897/phytokeys.207.61432 1314-2003-207-1 29CD4EF8FB525DBAA022DF25CDB649C9 Monanthotaxis bicornis (Boutique) Verdc., Kew Bull. 25(1): 31, 1971 Map 6D ≡ Popowia bicornis Boutique, Bull. Jard. Bot. Etat 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 miniere 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) .