Piptostigma oyemense Pellegr., Notul. Syst. (Paris) 14: 75, 1950

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 : 303-305

Piptostigma oyemense Pellegr., Notul. Syst. (Paris) 14: 75, 1950

Figs 91 , 93 ; Map 11I

Type.

Gabon. Woleu-Ntem; Oyem, Le Testu G.M.P.C. 9624, 21 Jun 1934: holotype: P[P00363276]; isotypes: BR[BR0000008802774, BR0000008802446]; BM[BM000553961]; P[P00363274, P00363275] .

Description.

Tree, 2-6 m tall, d.b.h. up to 10 cm; stilt roots or buttresses absent. Indumentum of simple hairs; old leafless branches glabrous, young foliate branches pubescent. Leaves: petiole 3-4 mm long, 1-2 mm in diameter, pubescent, cylindrical, blade inserted on top of the petiole; blade 11-27 cm long, 4-9 cm wide, elliptic, apex acuminate, acumen 0.2-2.5 cm long, base cuneate, papyraceous, below sparsely pubescent when young, glabrous when old, above glabrous when young and old, discolorous, whitish below; midrib impressed, above glabrous when young and old, below pubescent when young, glabrous when old; secondary veins 21 to 29 pairs, glabrous above; tertiary venation percurrent. Individuals bisexual; inflorescence cauliflorous, peduncle like base 7-10 mm long, axial internodes 3-6 mm long, compact, sympodial rachis 27-42 mm long. Flowers with 9 perianth parts in 3 whorls, 1 to 2 per inflorescence; pedicel 11-18 mm long, ca. 1 mm in diameter, pubescent; in fruit ca. 12 mm long, ca. 2 mm in diameter, pubescent; basal bract ca. ca. 4 mm long, 2 mm wide; upper bract ca. 4 mm long, ca. 2 mm wide; sepals 3, valvate, free, 5-6 mm long, 3-4 mm wide, ovate, apex acuminate, base truncate, brown, pubescent outside, glabrous inside, margins flat; petals free, outer petals shorter than inner; outer petals 3, 12-14 mm long, 3-4 mm wide, obovate, apex acuminate, base truncate, light green, margins flat, pubescent outside, glabrous inside; inner petals 3, valvate, 40-50 mm long, 5-10 mm wide, elliptic, apex acute, base truncate, pink, margins wavy, pubescent outside, pubescent inside; stamens numerous, in 6 to 8 rows, ca. 1 mm long, broad; connective discoid, glabrous, red; staminodes absent; carpels free, 3, ovary ca. 2 mm long, stigma globose, pubescent. Monocarps sessile, 1 to 3, 30-40 mm long, 25-30 mm in diameter, ellipsoid, apex rounded, pubescent when immature, glabrous when mature, verrucose, not ribbed, white with pink when ripe; seeds 3 to 5 per monocarp, 10-15 mm long, 5-10 mm in diameter, ellipsoid; aril absent.

Distribution.

Known from Cameroon to Gabon; in Cameroon known from South and South-West regions.

Habitat.

A rarely collected species in Cameroon; in rain forests on the slope of mountains. Altitude 450-900 m a.s.l.

Local and common names known in Cameroon.

None recorded.

IUCN conservation status.

Vulnerable B2ab(iii) ( Cosiaux et al. 2019a p).

Uses in Cameroon.

None reported.

Notes.

Piptostigma oyemense is characterized by its elliptic leaf blades, glabrous on both sides when old, and its inflorescence usually with a single flower (rarely 2) and 3 carpels. The only other species with a single flower per inflorescence and up few carpels (less than 4) is P. fugax , which has obovate to very narrowly obovate leaf blades, a cuneate leaf base (versus obtuse to acute), a pubescent midrib on the upper ide (versus glabrous), the longer inner petals between 20-40 mm long (versus 40-50 mm) and the tomentose monocarps (versus glabrous when mature).

Cheek and Cable (1998, p. 11) mention two specimens as Piptostigma sp. nov. (Akogo 34, Harris 3755) collected from Mont Cameroon. We identified the former as P. oyemense . We did not see Harris 3755.

Specimens examined.

South Region: Akom II, 2.78°N, 10.55°E, 12 December 2013, Kamdem N. 159 (YA). South-West Region : Bomana, 4.28°N, 9.060°E, 05 October 1993, Akogo M. 34 (K,YA) .

Figures

Map 11. A Piptostigma glabrescens B Piptostigma goslineanum C Piptostigma longepilosum D Piptostigma macranthum E Piptostigma macrophyllum F Piptostigma mayndongtsaeanum G Piptostigma mortehanii H Piptostigma multinervium I Piptostigma oyemense. White borders represent region limits in Cameroon; green patches represent protected areas (see methods and Suppl. material 1: Fig. S 1).

Figure 91. Piptostigma multinervium A habit, note numerous cauliflorous inflorescences along the trunk B base of leaf blade, upper side C base of leaf blade, lower side D flower, one inner petal removed E inflorescence with numerous flowers. Piptostigma oyemense F habit, note single flowered inflorescence G base of leaf blade, upper side H base of leaf blade, lower side I flower, note single flowered inflorescences J detail of receptacle, note 4 carpels K fruit, note white echinate to muricate monocarps A-E Couvreur 616, Ebo, Cameroon F, I-K Couvreur 917, Gabon G, H Couvreur 1139, Gabon. Photos Thomas L. P. Couvreur.

Figure 93. Piptostigma oyemense A branch (with a leaf and a flower) B receptacle C stamen D carpel side view and detail of ovules A-D from Le Testu 9624. Drawings by Helene Lamourdedieu, Publications Scientifiques du Museum national d'Histoire naturelle, Paris; 1 - 6 modified from Le Thomas (1969 b, pl. 21 (drawings 7 - 10), p. 123).