Monanthotaxis letouzeyi (Le Thomas) Verdc. — Plate, 1971

Hoekstra, P. H., Wieringa, J. J., Maas, P. J. M. & Chatrou, L. W., 2021, Revision of the African species of Monanthotaxis (Annonaceae), Blumea 66 (2), pp. 107-221 : 173-174

44. Monanthotaxis letouzeyi (Le Thomas) Verdc. — Plate 4d; Map 29

Monanthotaxis letouzeyi (Le Thomas) Verdc. (1971b) 31. — Popowia letouzeyi Le Thomas (1968) 241. — Type: R.G. Letouzey 3066 (holo P00362617 ; iso YA0002635 ), Cameroon, East Province, Nkoum, 19 Feb. 1960.

Liana, to 30 m long; young branches green, densely covered with erect, reddish brown hairs c. 0.4 mm long, becoming glabrous; old branches dark brown to blackish. Leaves: petiole (6–)7–10(–15) mm long, 2–3.4 mm diam, grooved, indument as on branches; lamina oblong-elliptic, obovate to oblanceolate, 6–23 by 6–12.2 cm, 1.6–2.9 times longer than wide, chartaceous, not punctate, discolorous, dark green above, glaucous below, above sparsely covered with hairs, becoming glabrous, primary vein densely covered with erect, reddish brown hairs, below densely covered with erect, yellow to reddish brown hairs c. 0.4 mm long, base rounded to subcordate, with thickened black margin, apex emarginate, rounded or rounded with small apicule to 10 mm long, secondary veins 14–19 per side, straight to slightly curving upwards, tertiary venation percurrent. ♂ Inflorescences cauliflorous, composed of 3–many-flowered fascicles or glomerules; sympodial rachis 5–25 mm long densely covered with erect, reddish brown hairs 0.2–0.4 mm long; pedicels 6–10 mm long, 0.8–1.2 mm diam, indument as on rachis; lower bracts absent; upper bracts c. halfway the pedicel, ovate, 0.6–1 by 0.8–1 mm, indument as on sympodial rachis; flower buds broadly ovoid; sepals slightly connate, elliptic to ovate, 1.1–1.2 by 0.7–0.8 mm, densely covered with reddish brown hairs; receptacle 1.2–1.4 mm diam, convex; petals colour in vivo unknown, 6, in two whorls, slightly connate at the base, outer petals depressed ovate, c. 3.5 by 4.7 mm, outside densely covered with erect, yellowish to reddish brown hairs, inside covered with few whitish to yellowish papillae c. 0.05 mm long, inner petals elliptic to ovate, 1.5–2.2 by 1–1.1 mm, outside and inside covered with yellowish papillae, apex covered with few hairs c. 0.05 mm long; stamens 31–40, in four whorls, free, oblong, 1.3–1.4 mm long, filaments 0.3–0.5 mm long, thecae extrorse, connective truncate, connective and filaments hairy, staminodes absent. ♀ Inflorescences cauliflorous, condensed many-flowered panicle-like rhipidia; sympodial rachis 2.5–4 cm long, densely covered with erect, reddish brown hairs 0.2–0.4 mm long; pedicels 8–15 mm long, 1.3–1.6 mm diam, fruiting pedicels 10–30 mm long, c. 2.1 mm diam, indument as on rachis; lower bracts ovate to broadly ovate, 0.7–2 by 1–1.5 mm, indument as on rachis; upper bracts in lower half of pedicel, size and indument as upper bracts; flower buds broadly ovoid; sepals slightly connate at base, ovate to depressed ovate, 1.5–1.7 by 1–2 mm, densely covered with reddish brown hairs; receptacle 2.5–3 mm diam, convex; petals colour in vivo unknown, 6, in two whorls, free; outer petals broadly ovate, 5–5.7 by 4.8–6.1 mm, outside densely covered with appressed, brownish hairs, inside densely covered with yellowish papillae and with few, yellowish hairs c. 0.05 mm long, inner petals spathulate, 1.8–2 by 1.2–1.4 mm, outside and inside densely covered with yellowish papillae; carpels c. 120, ellipsoid to rhombic, 1–1.2 by 0.5–0.7 mm, densely hairy, ovules 7 or 8, lateral, stigma ellipsoid to globse, 0.2–0.4 mm long, glabrous. Monocarps> 3, blackish green, moniliform, each part globose, 20–80 by 9–10 mm, smooth, rather densely covered with brownish hairs 0.2–0.4 mm long, apex rounded to slightly apiculate, apiculum to 0.5 mm long, stipes 7–10 mm long, slightly grooved to terete. Seeds 1–6, globose, c. 9 by 9 mm, reddish brown, both ends rounded, raphe not visible.

Distribution — Cameroon, Gabon, Republic of the Congo.

Habitat & Ecology — In evergreen forest, gallery forest, secondary forest and swamp forest on sandy clay. Altitude: 40– 850 m. Flowering: February, April, September, November; fruiting: March.

Preliminary IUCN conservation status — Least concern (LC). EOO: 264 066 km 2, AOO: 64 km 2. This species is known from 13 locations, five of which are protected areas. Several collections were made recently, and we do not consider this species under threat of extinction.

Note — Monanthotaxis letouzeyi can be recognized by the cauliflorous inflorescences and the dense indument of erect, reddish brown hairs c. 0.4 mm long on the young branches. Monanthotaxis letouzeyi can be confused with M. diclina , but that species has yellow-brown hairs and very different staminate flowers, which are axillary and have only 6 stamens and 12 staminodes, while M. letouzeyi has the staminate inflorescences cauliflorous and each flower has 31–40 stamens and no staminodes.

Figures

Plate 4 a–c. Monanthotaxis latistamina P.H.Hoekstra.a.Leaves;b. inflorescence;c.flowers. — d.Monanthotaxis letouzeyi (Le Thomas) Verdc.Leaves. — e–f. Monanthotaxis mannii (Baill.) Verdc. e. Leaves; f. leaves and flower (a–c: Couvreur 565; d: Couvreur 752; e–f: Jongkind 11848). — Photos: a–d: T.L.P. Couvreur; e–f: C.C.H. Jongkind.

Map 29 Distribution of Monanthotaxis letouzeyi (Le Thomas) Verdc. (■, D means uncertain dets) and M.littoralis (Bagsh.& Baker f.) Verdc.(●, Omeans uncertain det).