Monanthotaxis lucidula (Oliv.) 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 : 175-176

46. Monanthotaxis lucidula (Oliv.) Verdc. — Fig. 12e–j ; Map 30

Monanthotaxis lucidula (Oliv.) Verdc. (1971b) 27. — Unona lucidula Oliv. (1868) 35. — Popowia lucidula (Oliv.) Engl.& Diels (1901) 45. — Lectotype (designated by Paiva 1966): F.M.J. Welwitsch 762 (lecto LISU not seen; isolecto BM000553841), Angola, Malanje,distr.Pungo Adongo,barrancas da Pedra Songe ipsius Pruesidii, 731 m, Apr. 1857.

Unona lucidula Oliv.var. scandens Hiern (1896) 11. — Type: F.M.J.Welwitsch 770 (holo BM not seen; iso B100460924 , COI00004906 , LISU not seen, P00362641 ), Angola, Cuanza Norte, distr. Golungo Alto .

Shrub or liana, to 10 m long; young branches sparsely cover- ed with appressed, reddish brown hairs 0.2–0.3 mm long, becoming glabrous; old branches pale grey to pale brown. Leaves: petiole 3–6(–9) mm long, 0.8–1.4 mm diam, slightly grooved, indument as on branches; lamina obovate-oblong to oblanceolate, 7.8–16 by 2.6–6.6 cm, 1.8–3.5 times longer than wide, chartaceous, not punctate, glaucous below, strongly contrasting with reddish brown veins, above glabrous, but primary vein sparsely covered with appressed, yellow hairs 0.3–0.5 mm long, becoming glabrous, below sparsely covered with appressed, yellow hairs 0.2–0.4 mm long, becoming glabrous, hairs more contrasting on primary vein and veins, base cuneate, rounded to slightly subcordate, with thickened black margins, apex acute to acuminate, acumen to 20 mm long, secondary veins 8–16 per side, from base straight, halfway curving upwards, tertiary venation percurrent, hardly visible above. Inflorescences extra-axillary or leaf-opposed, composed of solitary flowers or more frequently of 2 – 6-flowered fascicle-like rhipidia; sympodial rachis 1–2.5 mm long, sparsely covered with appressed, yellow hairs 0.2–0.4 mm long; pedicels 5–21 mm long, 0.4–0.5 mm diam, fruiting pedicels 14–30 mm long, 1.1–1.4 mm diam, densely covered with appressed to ascending, yellow hairs; lower bract lanceolate, 2.8–4 by 0.9–1.2 mm, indument as on pedicel; upper bract in the lower half of the pedicel, ovate, 1.8–4 by 0.5–3 mm, indument as on pedicel; flower buds globose. Flowers bisexual; sepals free, covering petals in flower bud, ovate, 3.6–4.3 by 2.2–3.9 mm, apex acute, densely covered with appressed, yellow-brown hairs, persistent in fruit or slightly accrescent; receptacle c. 2 mm diam, flat; petals colour in vivo unknown, 6, in two whorls, outer petals broadly ovate, 3.5–7.2 by 3.4–5.7 mm, outside densely covered with yellow-brown, short hairs, inside covered with white-yellowish, very short hairs near the margins, inner petals narrowly elliptic to broadly ovate, 2.7–4.9 by 0.9–4.7 mm, outside densely covered with short hairs, inside glabrous, except for a few very short hairs near the apex and base; stamens 15, in one whorl, free, linear-oblong, 0.8–1.1 mm long, filaments c. 0.3 mm long, thecae latrorse to extrorse, connective truncate, prolonged outward, not hiding thecae, glabrous, staminodes absent; carpels 8–16, narrowly subcylindric-ellipsoid, 1.1–1.4 by c. 0.3 mm, densely hairy, ovules 2–4, lateral, stigma elongate, 0.3–0.5 mm long, glabrous. Monocarps 2 –15, colour in vivo unknown, moniliform, each part ellipsoid, 11–31 by 4.5–5.5 mm, slightly verrucose, sparsely covered with appressed hairs, becoming glabrous, apex apiculate, apiculum to 1 mm long, stipes 2–4.5 mm long. Seeds 1–4, ellipsoid, 7–9.5 by 4.2–5 mm, ochre-brown, apex flattened or rounded, raphe hardly visible.

Distribution — South Sudan, Democratic Republic of the Congo, Gabon, Republic of the Congo, Angola.

Habitat & Ecology — In primary mixed forest, secondary forest, swamp forest, gallery forest and Gilbertiodendron forest. Altitude: 300–1158 m. Flowering: January to May, September to November; fruiting: December to June, August.

Vernacular names — Democratic Republic of the Congo: Amapupu (J.F. Kahindo 86), Buba (Kibila name) (T.B. Hart 1238). Uganda: Umbusukundu (Zande name) (F.W. Andrews 1544).

Preliminary IUCN conservation status — Least concern (LC). EOO: 1 911 535 km 2, AOO: 136 km 2. This species has a wide distribution and occurs in many locations and there are a few recent collections.Therefore, this species is currently not under threat of extinction.

Notes — 1. Monanthotaxis lucidula is the only species of Monanthotaxis in Central Africa with the sepals covering the petals in bud. Vegetatively it can generally be recognized by the pale grey to pale brown branches and reddish brown secondary veins highly contrasting with the glaucous lower leafside. Monanthotaxis lucidula can be distinguished from other species with the sepals covering the petals in bud by the obovate to oblanceolate leaves and ovate sepals to 4.3 mm long.

2. There is some variation in the vegetative characters of M. lucidula across the distribution. In the west of the distribution area the branches are more pale brown, while in the east of Congo the branches are more grey-brown and the young branches are more densely hairy.

Figures

Map 30 Distribution of Monanthotaxis lucidula (Oliv.) Verdc.

Fig. 12 a–d. Monanthotaxis littoralis (Bagsh. & Baker f.) Verdc. a. Flowering branch; b. stamen, front and side view; c. carpel; d. fruiting branch. — e–j. Monanthotaxis lucidula (Oliv.) Verdc. e. Flowering branch; f. flower bud with sepals removed, seen from below; g. flower bud seen from above; h. stamen, side and front view; i. carpel; j. fruiting branch. — k–q. Monanthotaxis ferruginea (Oliv.) Verdc. k. Flowering branch; l. flower bud; m. flower seen from above; n. stamen, front and side view; o. carpel; p. fruiting branch; q. longitudinal sections of carpels (a–c: Koechlin 671; d: Thollon 938; e–i: Bouquet 792; j: Hallé 3539; k–q: living material of Hallé 3081 & 3103). — Modified from Le Thomas (1969) plate 40.