Monanthotaxis diclina (Sprague) Verdc.

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 : 145-146

19. Monanthotaxis diclina (Sprague) Verdc. — Fig. 9f–n ; Plate 2f ; Map 13

Monanthotaxis diclina (Sprague) Verdc. (1971b) 31, non M. mannii (Baill.) Verdc. (1971b) . — Clathrospermum mannii Oliv. (1868) 25, p.p., quoad Mann 960. — Popowia mannii (Oliv.) Engl. & Diels (1901) 49, p.p., quoad Mann 960, nom.illeg.,non Popowia mannii Baill.(1868) 320. — Popowia diclina Sprague (1908) 53,p.p., quoad Mann 960; Chipp (1923) 182. — Lectotype (selected by Le Thomas,1969:216): G. Mann 960 (lecto K000198989), Gabon, Estuaire, Gaboon River, July 1861.

Popowia caulantha Exell (1932) 208. — Type: J. Gossweiler 6721 (holo BM000553848 ;iso COI 00004904 , LISC000104 , LISC000264 , LISC000265 , LISC000266 , LISU), Angola, Cabinda, BucoZau-Maiombe, na colina próximo do posto administrative, 29 Sept. 1916.

Liana, to 25 m long; young branches densely covered with erect to curly, yellow-brown hairs 0.4–0.6 mm long, becoming glabrous; old branches dark brown. Leaves: petiole 3–5 mm long, 1.5–2 mm diam, grooved, indument as on branches; lamina oblong-elliptic, obovate to oblanceolate, 8.5–18.2 by 3.5–6.9 cm, 2.4–2.9(–3.5) times longer than wide, chartaceous to subcoriaceous, not punctate, discolorous, glossy dark green above, glaucous below, above sparsely covered with few, white to yellow hairs 0.3–0.5 mm long, primary vein densely covered with erect, yellow hairs, below densely covered with erect yellow hairs c. 0.5 mm long, base rounded to subcordate, with thickened black margin, apex acute to almost rounded, secondary veins 15–19 per side, 10–12 per side on young leaves, straight to curving upwards, tertiary venation percurrent. Flowers unisexual. ♂ Inflorescences axillary or ramiflorous, composed of solitary flowers to few-flowered fascicles, sometimes up to 25-flowered rhipidia; sympodial rachis 1–3 mm long, densely covered with erect, yellow-brown hairs 0.3–0.4 mm long; pedicels 2–5 mm long, c. 0.4 mm diam, densely covered with erect, yellow-brown hairs; bracts ovate, c. 0.5 by 0.4 mm, indument as on rachis; flower buds depressed globose; sepals slightly connate at the base, broadly ovate, c. 0.5 by 0.5 mm, densely covered with appressed, brown hairs, persistent in fruit; receptacle 1–1.2 mm diam, convex; petals yellowish brown, 6, in two whorls, outer petals depressed ovate, c. 1.6 by 2 mm, outside densely covered with yellowish brown, short hairs, inside covered with yellowish hairs c. 0.05 mm long, inner petals elliptic, 0.5–0.8 by 0.3–0.4 mm, outside and the apex of the inside, covered with yellowish hairs c. 0.05 mm long, base of inside glabrous; stamens 6, in one whorl, in pairs, free, oblong, 0.8–0.9 mm long, filaments 0.3–0.4 mm long, thecae latrorse, connective truncate, sparsely hairy, staminodes 12, in one whorl 0.2–0.3 mm long, sparsely hairy. ♀ Inflorescences cauliflorous, glomerules or condensed, many-flowered panicle-like rhipidia; sympodial rachis 1.5–6 cm long, to 9 cm long in fruit, densely covered with erect, yellowish brown hairs c. 0.5 mm long; pedicels 15–25 mm long, 0.9–1 mm diam, fruiting pedicels to 45 mm long, 1.1–1.6 mm diam, densely covered with erect, yellowish brown hairs; bracts ovate, 1.3–1.7 mm long, indument as on sympodial rachis; flower buds globose to slightly ovoid; sepals free or slightly connate, broadly ovate, 1.2–1.7 by 1.3–1.4 mm, densely covered with appressed, brown hairs, persistent in fruit; receptacle 1.6–2 mm diam, convex to globose; petals pale brown on the outside, creamy on the inside, 6, in two whorls, outer petals broadly ovate, 3–5 by 3.5–5.4 mm, outside densely covered with appressed brown hairs 0.2–0.3 mm long, inside covered with yellowish hairs c. 0.05 mm long, inner petals elliptic, 1.3–1.7 by 0.6–0.7 elliptic, outside and inside covered with yellowish hairs c. 0.05 mm long; carpels 80–100, narrowly ellipsoid, 1.3–1.4 by 0.3–0.4 mm, densely hairy, ovules 4 or 5, lateral, stigma elongate, c. 0.2 mm long, grooved, glabrous. Monocarps up to 14, medium green when ripe, narrowly ellipsoid to moniliform, 23–55 by 7–8 mm, slightly verrucose, rather densely covered with erect to curly, brownish hairs 0.3–0.4 mm long, apex apiculate, apiculum 0.5–1 mm long, stipes (6–)8–11(–14) mm long, slightly grooved. Seeds 1–5, ellipsoid, 12–15 by 6–8.5 mm, reddish brown, both ends rounded, raphe slightly visible as a longitudinal furrow from base to apex.

Distribution — Cameroon, Gabon, Republic of the Congo, Angola.

Habitat & Ecology — In primary forest, old secondary forest, submontane forest, swamp forest and gallery forest. Altitude: 30– 650 m. Flowering and fruiting all year round.

Preliminary IUCN conservation status — Least concern (LC). EOO: 277 679 km 2, AOO: 172 km 2. This species is known from many locations and recent collections. It is one of the com- monest species of Monanthotaxis encountered in the forests of Gabon.

Notes — 1. Monanthotaxis diclina can be distinguished from all other Monanthotaxis species with unisexual flowers by the dense indument of yellowish brown hairs to 0.5 mm long on the young branches and lower side of the leaves. Other species have reddish brown hairs or shorter hairs.

2. The sterile specimens W.D. Hawthorne 2262 and C.C.H. Jongkind 8515 from Liberia look very similar to M. diclina . These would be the first records of the species in West Africa, and flowering or fruiting material is needed to assess whether they represent M. diclina . The specimen cited in Keay (1954) as M. diclina from Liberia probably is more similar to M. velutina than to M. diclina .

3. Exell (1932) explicitely mentions that his paper is based on material that was sent to BM, hence we consider the BM sheet of J. Gossweiler 6721 as the holotype of Popowia caulantha .

Figures

Plate 2 a. Monanthotaxis buchananii (Engl.) Verdc. Flowering branch. — b. Monanthotaxis caffra (Sond.) Verdc. Flowering branch. — c–e. Monanthotaxis couvreurii P.H.Hoekstra. c. Leaves; d. inflorescence; e. flower. — f. Monanthotaxis diclina (Sprague) Verdc.Pistillate inflorescence with flower buds and young fruits (a: J. Burrows 9828; b: Wieringa 8018; c–e: Couvreur 762; f: Couvreur 537). — Photos: a: M.C. Lötter; b: J.J. Wieringa; c–f: T.L.P. Couvreur.

Map 13 Distribution of Monanthotaxis diclina (Sprague) Verdc. (■) and M. dielsiana Engl. (●, O means uncertain dets).

Fig. 9 a–e. Monanthotaxis confusa P.H.Hoekstra. a. Staminate flowering branch; b. staminate flower,outer petal,inside view; c. staminate flower, inner petal, inside view; d. staminate flower with petals removed; e. stamen, outer and side view. — f–n. Monanthotaxis diclina (Sprague) Verdc. f. Staminate flowering branch; g. staminate flower with one outer petal removed; h. staminate flower inner petal, inside view; i. stamen, outside and inside view; j. staminate flower staminode; k. pistillate flower, outer petal, inside view; l. pistillate flower, inner petal, inside view; m. carpel and longitudinal section of carpel; n. fruits. — o–s. Monanthotaxis glomerulata (Le Thomas) Verdc.o. Pistillate inflorescence; p. pistillate flower with one outer petal removed;q. pistillate flower, outer petal,inside view; r. pistillate flower, inner petal, inside view; s. carpel and longitudinal section carpel (a–e: Lebrun 6134; f–j: Klaine 2881; k–m: Klaine 1382; n: Klaine 404; o–s: Le Testu 8700). — Modified from Le Thomas (1969) plate 38.