Monanthotaxis oligandra Exell

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 : 184

55. Monanthotaxis oligandra Exell — Map 35

Monanthotaxis oligandra Exell (1932) 209. — Type: J. Gossweiler 6043 (holo BM000547353 ;iso COI00004908 , LISC000268 ), Angola,Cabinda, Pongo Monga, Mayombe, 27 Dec. 1915.

Scandent shrub or liana, 1–7 m long, c. 0.5 cm diam; young branches reddish brown, covered with appressed to ascending, yellowish hairs c. 0.2 mm long, becoming glabrous; old branches blackish. Leaves: petiole 2–4 mm long, 1–1.4 mm diam, grooved, indument as on branches; lamina oblong-elliptic

Map 35 Distribution of Monanthotaxis oligandra Exell (▲), M. paniculata P.H.Hoekstra (■, Dmeans uncertain dets)and M.pellegrinii Verdc. (●, Omeans uncertain det).

to obovate or narrowly so, 7–15.4 by 3.4–5.9 cm, 1.7–2.9 times longer than wide, chartaceous, punctate, ash-grey below, above sparsely covered with hairs to 0.4 mm long, soon becoming glabrous, below sparsely covered with appressed to ascending, whitish hairs 0.2(–0.4) mm long, more densely so on the primary vein, base rounded to subcordate with thickened margin, apex acute to acuminate, secondary veins 8–12 per side, curving upwards, tertiary venation percurrent. Inflorescences supra-axillary, originating 2–8(–16) mm above axil, 1–6-flowered rhipidia; sympodial rachis 2.7–3.6 cm long, covered with erect, yellowish hairs c. 0.3 mm long; pedicels 0.7–1.5 mm long, 0.2–0.3 mm diam, fruiting pedicels to 60 mm long; indument as on rachis; lower bracts absent; upper bract placed at the nodes in the inflorescence, lanceolate, 1.1–2 by 0.2–0.4 mm, densely covered with hairs; flower buds globose. Flowers bisexual; sepals free at the base, broadly ovate, 0.6–1 by 0.8–0.9 mm, apex acute, outside densely covered with appressed hairs, inside glabrous except for the hairy edges; receptacle 0.7–1.2 mm diam, flat; petals tawny at the outside, inside cream, 6, in one whorl, ovate, 1.5–2 by 1–1.5 mm, outside densely covered with hairs c. 0.1 mm long, inside at the apex covered with hairs c. 0.05 mm to papillate, base glabrous; stamens 6, in one whorl, free, obconical, 0.4–0.8 mm long, filaments 0.1–0.3 mm long, thecae extrorse, connective truncate, slightly prolonged outward, papillate, staminodes absent; carpels 7, ellipsoid, c. 0.8 by 0.4 mm, densely covered with yellowish hairs, ovules 2, lateral, stigma globose, c. 0.1 mm diam, grooved, glabrous. Monocarps 6, colour in vivo unknown, narrowly ellipsoid to subcylindric, 16–18 by 4–5 mm, constricted between the seeds, slightly verrucose, densely covered with appressed, reddish brown hairs, becoming glabrous, apex apiculate, apiculum 2–3 mm long, stipes c. 4 mm long, terete. Seeds 1 or 2, ellipsoid to cylindric, 9–12 by 4–5 mm, tawny-brown, seed ends apiculate, apiculum c. 0.5 mm long, raphe visible on both sides.

Distribution — Democratic Republic of the Congo (Bas-Congo), Angola ( Cabinda).

Habitat & Ecology — In forest and secondary forest. Flowering: January, March, December; fruiting: April, June, July.

Preliminary IUCN conservation status — Endangered (EN): B2ab(iii). EOO: 1 517 km 2, AOO: 24 km 2. This species is only known from a few locations from a small area near the border of Angola and the Democratic Republic of the Congo. Furthermore, it has only been collected once in the last 50 years.

Note — Monanthotaxis oligandra is easily recognised by the supra-axillary rhipidium. This character is only shared with the allopatric M. letestui . It can be distinguished from that species by the number of stamen (6 vs 12–14) and the sparsely hairy lower leafside.