Monanthotaxis paniculata P.H.Hoekstra, Phytotaxa 186(2): 106, 2014

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 : 223-226

Monanthotaxis paniculata P.H.Hoekstra, Phytotaxa 186(2): 106, 2014

Figs 65 , 66 ; Map 8G

Type.

Gabon. Ogooué-Ivindo; north of Koumameyong along SHM lumber roads, McPherson G.D. 16123, 31 Jan 1993: holotype: WAG[WAG0357246, WAG0357247]; isotypes: LBV n.v., MO n.v., P[P01967243] .

Description.

Liana, 20 m tall, d.b.h. unknown. Indumentum of simple hairs; old leafless branches glabrescent, young foliate branches densely pubescent with appressed reddish-brown hairs 0.5 mm long. Leaves: petiole 4-8 mm long, ca. 1 mm in diameter, densely pubescent, slightly grooved, blade inserted on top of the petiole; blade 8.5-23.5 cm long, 3.3-6.6 cm wide, ovate to oblanceolate, apex acuminate to acute, acumen 0.5-2.7 cm long, base cuneate to broadly cuneate with small linear black glands, chartaceous, below densely pubescent with yellowish hairs when young, sparsely pubescent to glabrous when old, above sparsely pubescent when young, glabrous when old, discolorous, whitish below; midrib impressed, above glabrous when young and old, below sparsely pubescent when young and old; secondary veins 10 to 16 pairs, glabrous above; tertiary venation percurrent. Individuals bisexual; inflorescences ramiflorous on old leafless branches, axillary or terminal. Flowers with 9 perianth parts in 2 whorls, numerous per inflorescence, peduncle 5.5-27 cm long, panicle-like; pedicel 5-27 mm long, 0.5-1 mm in diameter, densely pubescent with short reddish brown hairs; in fruit 20-30 mm long, 2-3 mm in diameter, pubescent; bracts 2, one basal and one upper towards the middle or lower half of pedicel, basal bract 1-8 mm long, ca. 1 mm wide; upper bract ca. 1 mm long, ca. 1 mm wide; sepals 3, valvate, free, 0.5-1 mm long, 1-1.5 mm wide, broadly ovate, apex obtuse, base truncate, densely pubescent outside, glabrous inside, margins flat; petals free, petals 6 in one whorl, ca. 3 mm long, ca 1.5 mm wide, ovate, apex rounded to obtuse, base truncate, margins flat, sparsely pubescent outside, sparsely pubescent inside; stamens 6, in 1 row, inserted on a black hexagonal disc, opposite to the petals, free at the base, ca. 1 mm long, obconic; connective truncate, kidney-shaped in dorsal view, glabrous; staminodes 6, alternating with the stamens, glabrous; carpels free, 14 to 24, ovary ca. 2 mm long, stigma shortly bilobed, acute, glabrous. Monocarps stipitate, stipes 3-4 mm long, 3-4 mm in diameter; monocarps 2 to10, 15-30 mm long, 10-15 mm in diameter, not moniliform, ellipsoid, apex rounded, pubescent, smooth, green when ripe; seed 1 per monocarp, ca. 10 mm long, ca. 8 mm in diameter, ellipsoid; aril absent.

Distribution.

A central African species from Gabon and Cameroon; in Cameroon known from Littoral and South regions.

Habitat.

A rare species in Cameroon; in lowland primary or old secondary rain forests. Altitude 300-350 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 reported.

Notes.

Monanthotaxis paniculata is distinguished by the long appressed yellowish pubescence on lower side of the leaf blade, its inflorescence in a large panicle-like rhipidium (unique in the genus) and its flowers with one whorl of 6 petals. It is morphologically close to M. congoensis , but differs by its panicle-like inflorescence, depressed-globose floral buds, stamens inserted on a black hexagonal disc, and connective appendage kidney-shaped in dorsal view.

Fruits were unknown when the species was first published ( Hoekstra et al. 2014) but have since been collected (Couvreur 1108) and fruits are described here for the first time.

The presence of Monanthotaxis paniculata in Cameroon is only based on two sterile collections, and needs to be confirmed with fertile material.

Specimens examined.

Littoral Region: Mambe Massif above Boga village 100 km along road from Yaoundé to Ed 3.90°N, 10.77°E, 19 June 2014, Couvreur T.L.P. 651 (WAG,YA) . South Region: Campo Ma’an National Park 11 km on trail from Ebinanemeyong village on road 7 km from Nyabessan to Campo town , 2.47°N, 10.34°E, 14 February 2015, Couvreur T.L.P. 708 (WAG,YA) .

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 65. Monanthotaxis paniculata A flowering branch B flower bud C flower with three petals removed D petal outer, side view E petal, inner view F stamen inner, side view G stamen, side view H stamen, outer view I stamen, top view J staminode K carpel A-J from G. D. McPherson 16123 K from Reitsma 2870. Drawings by Esmee Winkel (Hoekstra et al. 2021, fig. 23, p. 186).

Figure 66. Monanthotaxis paniculata A fruiting branch, note long paniculate inflorescences B base of leaf blade, upper view C base of leaf blade, lower view D fruiting branch, note long paniculate inflorescences E fruit, with longitudinal section of one monocarp. Monanthotaxis sterilis F habit, juvenile G leaves, upper side, note linear blades H base of leaf blade, upper view I base of leaf blade, lower view A-E Couvreur 1108, Gabon F-I Couvreur 628, Ebo, Cameroon. Photos Thomas L. P. Couvreur.