Monanthotaxis biglandulosa (Boutique) P.H.Hoekstra, 2021

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 : 133

8. Monanthotaxis biglandulosa (Boutique) P.H.Hoekstra , comb. nov. — Fig. 6i ; Map 5

Monanthotaxis biglandulosa ( Boutique) P.H.Hoekstra , comb. nov. — Enneastemon biglandulosus Boutique, Bull. Jard. Bot. État Bruxelles 21 (1951b) 125. — Lectotype (designated here): J.A.A. Gillardin 183 (lecto BR ( BR0000008820440 );iso BR0000008820266 , BR0000008820273 ), Democratic Republic of the Congo, Kasai-Oriental , Kanda Kanda , Concession Laridon, Versaut vallée, 940 m, 4 Dec. 1936.

Shrub or liana, to 3 m long; young branches densely covered with ascending, yellowish brown hairs 0.2–0.4 mm long, becoming glabrous; old branches grey-black. Leaves: petiole 2.5– 4.5 mm long, 1.5–1.7 mm diam, terete, indument as on branches; lamina elliptic to narrowly elliptic-obovate, 8.2–15.7 by 2.8–7.1 cm, 2.2–3.5 times longer than wide, chartaceous, not punctate, above sparsely covered with appressed, whitish hairs 0.2–0.3 mm long, primary vein more covered with ascending, yellowish hairs, below sparsely covered with appressed, yellow hairs c. 0.2 mm long, primary vein densely covered with appressed to ascending hairs, base slightly cuneate to rounded, with or without thick, globose, black glands, apex acute to acuminate, acumen to 15 mm long, secondary veins 7–13 per side, slightly curving upwards towards the margin, tertiary venation percurrent, hardly visible above. Inflorescences axillary, composed of solitary flowers to 3-flowered fascicle-like rhipidia; sympodial rachis 0–12 mm long, densely covered with ascending, yellowish hairs; pedicels 7–25 mm long, 0.4–0.6 mm diam, fruiting pedicels 22–35 mm long, 0.7–1.2 mm diam, densely covered with ascending, yellow hairs; lower bracts absent or a dense tuft of yellow-brown hairs; upper bract in the lower half of the pedicel or to almost halfway, ovate, 0.7–1.2 by 0.4–0.7 mm, densely covered with hairs as pedicels; flower buds globose. Flowers bisexual; sepals connate at the base, depressed ovate to shallowly triangular, 0.7–1 by 1.5–1.7 mm, apex acute, densely covered with appressed hairs, persistent in fruit; receptacle 1.5–2 mm diam, flat; petals colour in vivo unknown, 6, in two whorls, base of inner petals visible in bud, outer petals ovate, 3.5–4.2 by 2.3–3.7 mm, outside densely covered with appressed, yellowish brown hairs c. 0.2 mm long, but hairs shorter and ascending near the apex of the inside and glabrous at the base, inner petals rhombic, 2.9–3.1 by 2–2.1 mm, outside and apical part on inside covered with yellowish brown, short hairs; stamens 9, in one whorl, free, clavate, 1.3–1.6 mm long, filaments 0.8–1 mm long, thecae extrorse, connective truncate, prolonged outward and inward, hiding thecae, glabrous, but sparsely hairy on the underside of the inward extension, staminodes absent; carpels 10–14, subcylindric, 1.3–1.6 by c. 0.5 mm, densely hairy, ovules 5 or 6, lateral, stigma elongate, 0.4–0.5 mm long, glabrous. Monocarps 1–7, colour yellowish brown, moniliform,18–39 by 6–8 mm, slightly verrucose, covered with appressed, yellowish brown hairs, apex apiculate, apiculum 1–4 mm long, stipes 7–11 mm long. Seeds 1–5, subcylindric to ellipsoid, 13–18 by 5–8 mm, ochre-brown, apex rounded, raphe visible or not.

Distribution — Democratic Republic of the Congo (Kasai-Oriental, Katanga, Maniema, Orientale), Angola (Lunda Norte).

Habitat & Ecology — In primary rain forest, secondary rain forest and gallery forest. Altitude: 470– 995 m. Flowering: February, May, December; fruiting: April, May.

Vernacular name — Democratic Republic of the Congo: Lukukuma (R. Desenfans 5176).

Preliminary IUCN conservation status — Endangered (VU): B2ab(iii). EOO: 438 453 km 2, AOO: 28 km 2. This species is known from 7 scattered locations of which 4 fall outside reserves.

Notes — 1. Verdcourt (1971b) refrained from changing Enneastemon biglandulosus to Monanthotaxis biglandulosa , because he was not sure if this species should be synonymised with M. schweinfurthii as the size of the leaf glands varies. However, M. biglandulosa differs from the latter in having 10 –14 carpels per flower, while M. schweinfurthii consistently has 6 carpels. Furthermore, the sympodial rachis in M. biglandulosa is generally 4 –12 mm long and the seeds are normally subcylindric, while the sympodial rachis is generally absent or up to 1 mm long in M. schweinfurthii and the seeds are ellipsoid to subglobose.

2. P. Bamps 500 differs from the other specimens in having appressed instead of ascending hairs on the young branches.

Figures

Map 5 Distribution of Monanthotaxis bicornis Boutique (●, O means uncertain det) and M. biglandulosa (Boutique) P.H.Hoekstra (■).

Fig. 6 a. Monanthotaxis seretii (De Wild.) P.H.Hoekstra. Fruiting branch. — b–h. Monanthotaxis capea (E.G.Camus & A.Camus) Verdc. b. Flower bud, seen from above; c. flower bud, side view; d. stamen, outer, inner and side view; e. carpel; f. fruiting branch; g. fruiting branch; h. seed. — i. Monanthotaxis biglandulosa (Boutique) P.H.Hoekstra. Fruiting branch. — j–m. Monanthotaxis foliosa (Engl. & Diels) Verdc. j. Flowering branch; k. flower bud, seen from above; l. stamen,outer and side view; m.carpel (a: J.L.P. Louis 11405; b–h: Hallé 3561; i: Bamps 600; j–m: Le Testu 2108). — Modified from Le Thomas (1969) plate 44.