Monanthotaxis cauliflora (Chipp) 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 : 139-140

13. Monanthotaxis cauliflora (Chipp) Verdc. — Map 9

Monanthotaxis cauliflora (Chipp) Verdc. (1971b) 30. — Popowia cauliflora Chipp (1923) 182. — Lectotype (designated by Le Thomas 1969: 218): W.C.Thomson s.n. (lecto K000198911;isolecto P not seen), Nigeria, Cross River State, Old Calabar, 1863.

Clathrospermum mannii auct.non Oliv.:Oliv. (1868) 25, p.p., quoad specim. ♀. — Popowia mannii auct. non (Oliv.) Engl. & Diels: Engl. & Diels (1901) 49,p.p., quoad specim. ♀. — Popowia diclina auct.non Sprague: Sprague (1908) 53, p.p., quoad specim. ♀.

Liana, to 25 m long, to 3.5 cm diam; young branches dark brown to blackish, covered with erect, reddish brown hairs 0.05– 0.1 mm long, becoming glabrous; old branches dark brown. Leaves: petiole 5–9 mm long, 1.2–2.1 mm diam, grooved, indument as on branches; lamina oblong-elliptic to oblanceolate, 12.5–15.2 by 4.8–5.8 cm, (2–)2.2–3.1(–3.9) times longer than wide, chartaceous, not punctate, glaucous below, above glabrous except primary vein densely covered with yellowish hairs c. 0.1 mm long, below sparsely covered with white hairs to 0.4 mm long, becoming glabrous, veins more densely covered with appressed to slightly erect hairs, base rounded to cuneate, with thickened black margin, apex acute to acuminate, acumen to 10 mm long, secondary veins 11–16 per side, straight, tertiary venation percurrent. Flowers unisexual. ♂ Inflorescences axillary, composed of solitary flowers to up to 6-flowered fascicles; sympodial rachis 2 –15 mm long, densely covered with hairs c. 0.1 mm long; pedicels 5–6 mm long, 0.3–0.4 mm diam, densely covered with reddish brown hairs c. 0.05 mm long; bracts ovate, 0.5–0.7 by 0.3–0.4 mm, indument as on rachis; flower buds depressed globose; sepals slightly connate basally, broadly triangular, 0.5–0.8 by 0.5–0.7 mm, densely covered with very short hairs; receptacle 0.6–1.1 mm diam, convex; petals colour in vivo unknown, 6, in two whorls, outer petals depressed ovate, 1.2–2.3 by 1.9–2.7 mm, outside densely covered with brownish hairs, inside covered with yellowish, very short papillae, inner petals elliptic, 0.5–0.7 by 0.3–0.5 mm, outside and inside covered with yellowish to whitish, very short hairs; stamens 6, in one whorl, in groups of 2, oblong, 0.7–1.1 mm long, filaments 0.1–0.3 mm long, thecae latrorse, connective truncate, sparsely hairy, staminodes 12 (or 13), c. 0.2 mm long, sparsely hairy. ♀ Inflorescences cauliflorous, condensed, many-flowered panicles to c. 12 cm diam; sympodial rachis 1.5–10 cm long, densely covered with reddish brown hairs c. 0.1 mm long; pedicels 6–20 mm long, 0.6–0.8 mm diam, fruiting pedicels 30–40 mm long, 1.1–1.8 mm diam, densely covered with reddish brown, very short hairs; bracts ovate to broadly ovate, 1–1.6 by 0.7–0.9 mm, indument as on rachis; flower buds depressed globose; sepals free to basally slightly connate, ovate to lanceolate, 0.7–1.3(–1.8) by 0.4–0.6(–1.4) mm, densely covered with appressed, very short hairs; receptacle 1.2–1.3 mm diam, convex; petals dull green on the outside, yellowish on the inside, 6, in two whorls, outer petals depressed ovate, 2.8–3.3(–4.2) by 3.7–4(–5) mm, outside densely covered with appressed, yellowish brownish hairs 0.1– 0.2 mm long, inside covered with yellowish, very short papillae, inner petals elliptic, 1.3–1.4 by 0.5–0.6 mm, outside and inside covered with yellowish, very short hairs; carpels 48–60(–76), ellipsoid, 1.2–1.4 by 0.4–0.5 mm, densely hairy, ovules 5 or 6, lateral, stigma elongate, 0.2–0.4 mm long, grooved, glabrous. Monocarps up to 8, narrowly ellipsoid to ellipsoid, 15–57 by 6–9 mm, constricted between the seeds, smooth to slightly verrucose, rather densely covered with yellowish hairs 0.1–0.2 mm long, becoming glabrous, apex apiculate, apiculum 0.5–1 mm long, stipes (6–) 9–12 mm long, slightly grooved. Seeds 1–4, ellipsoid, 12–15 by 5–8 mm, yellowish brown to reddish brown, both ends rounded, raphe not visible.

Distribution — Cameroon, Equatorial Guinea, Gabon.

Habitat & Ecology — In primary rain forest, old secondary forest and gallery forest. Altitude: 50– 720 m. Flowering: January, August; fruiting: February, June.

Preliminary IUCN conservation status — Vulnerable (VU). EOO: 67 001 km 2, AOO: 64 km 2. This species is known from 17 collections from 9 locations of which 2 in national parks and one in a nature reserve. However, the majority of collections are very old and the last collections from Nigeria and Gabon are more than 50 years old.

Note — Monanthotaxis cauliflora resembles M. diclina and M. pynaertii . Typical specimens are easily distinguishable by their very short indument on the young branches and lower side of the leaves and the smaller pistillate flowers with 48–60 carpels. In the south of Cameroon and very north of Gabon M. cauliflora and M. diclina occur sympatrically and some intermediate forms can be found. J.J. Bos 6037, for example, has large pistillate flowers with up to 76 carpels and is therefore intermediate between M. diclina and M. cauliflora , however, the indument is more like M. cauliflora than M. diclina . All other specimens of M. cauliflora can be distinguished by the staminate flowers, which have 6 stamens and 9 very small staminodes.

Figures

Map 9 Distribution of Monanthotaxis capea (E.G.Camus & A.Camus) Verdc. (■) and M. cauliflora Chipp (●, O means uncertain dets).