Monanthotaxis orophila (Boutique) 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 : 184-185

56. Monanthotaxis orophila (Boutique) Verdc. — Map 36

Monanthotaxis orophila ( Boutique) Verdc. (1971b) 27. — Popowia orophila Boutique (1951b) 112. — Lectotype (designated by Verdcourt 1971a:100): J.­H. Humbert 7530 (lecto consisting of 2 sheets: BR0000008802019 , BR0000008802675 ;iso G00308337 , P00362630 , P00362632 , P00362633 ), Democratic Republic of the Congo,Sud-Kivu,Kabare,montagnes à l’Ouest du Lac Kivu, Marais Kanzibi, 2200 m, 1 Feb. 1929.

Monanthotaxis germainii ( Boutique) Verdc. (1971b) 26, syn. nov. — Popowia germainii Boutique (1951b) 113.— Lectotype (designated by Verdcourt 1971a: 101): R.G.A. Germain 3164 (lecto BR0000008805287 ; iso BM000553836 , K000198986 ), Democratic Republic of the Congo, Nord-Kivu , Rutshuru, Rumangabo, 27 Dec. 1944.

Shrub, scandent shrub or liana, to 15 m long and 3 cm diam; young branches covered with appressed, yellow-brown hairs 0.1–0.2 mm long, becoming glabrous; old branches blackish to dark brown. Leaves: petiole (3–)5–9(–12) mm long, 0.8–1.3 mm diam, grooved, indument as on branches; lamina oblong-elliptic to narrowly oblong-obovate, 3.5–15.5 by 1.2–6.2 cm, 2.3–3.3 times longer than wide, subcoriaceous, not punctate, above glabrous, below glabrous, except for a few, appressed hairs c. 0.1 mm long on primary vein, base obtuse, rounded to subcordate, with thickened black margin, apex obtuse, acute to often shortly acuminate, acumen to 10 mm long, secondary veins 6–12 per side, curving upwards, tertiary venation reticulate, raised above. Inflorescences terminal, leaf-opposed or sometimes extra-axillary, composed of solitary flowers; sympodial rachis 3–8 mm long, sparsely covered with appressed, yellowish brown hairs; flowering pedicels 10–26 mm long, 0.4–0.5 mm diam, fruiting pedicels 0.6–1 mm diam, indument as on rachis; lower bract absent; upper bract near base of pedicel, large and leafy, broadly ovate to ovate, base semi-amplexicaul, 5–21 by 5–11 mm, glabrous except for few hairs at the margins; flower buds globose. Flowers bisexual; sepals connate at the base, depressed ovate to shallowly triangular, 2–2.3 by 3–3.5 mm, apex acute, sparsely covered with appressed hairs; receptacle 2.5–3 mm diam, flat; petals greenish to yellowish green, 6, in two whorls, outer petals ovate to broadly ovate, 5–9.5 by 5.5–7.5 mm, outside densely covered with yellow-brown, short hairs, inside densely covered with yellow, short hairs, glabrous at the base, inner petals rhombic to elliptic, narrowed at the base, not covering stamens entirely in bud, 5.2–7.6 by 3.3–5 mm, outside densely covered with very short hairs, inside glabrous at the base; stamens 24–34, in two or three whorls, free, linear-obconical, 1.8–2.3 mm long, filaments 0.8–1.3 mm long, thecae latrorse, connective truncate, square, pentagonal to rhombic seen from above, glabrous, staminodes absent; carpels (7–)11–17, narrowly subcylindric-ellipsoid, c. 2 by 0.5 mm, densely hairy, ovules 4–6, lateral, stigma elongate, 0.5–0.7 mm long, 2-lobed at the apex, glabrous. Monocarps 2 –11, red when ripe, moniliform, 19–55 by 6–9 mm, each part ellipsoid, covered with few, appressed hairs at the stipe, apex apiculate, apiculum to 3 mm long, stipes 9–17 mm long. Seeds 1–6, ellipsoid, 14–18 by 6–7 mm, tawny, apex apiculate, raphe not visible.

Distribution — Democratic Republic of the Congo, Uganda, Rwanda, Burundi.

Habitat & Ecology — In submontane evergreen forest, montane forest, gallery forest and secondary forest on basalt and syenite. Altitude: 1220–2700 m. Flowering and fruiting all year round.

Vernacular names — Burundi: Umukonyantoki (Kirundi name) (J. Lewalle 4313). Democratic Republic of the Congo: Lukumbula (Kiviga name) (R. Gutzwiller 1984). Rwanda:Uruhetza (P.A.J. B. van der Veken 10949), Urukenke (G. Bouxin 1319), Ingani-gani (G. Bouxin 665), Uruhashya (B. Runyinya 811).

Preliminary IUCN conservation status — Least concern (LC). EOO: 75 845 km 2, AOO: 136 km 2. This species is known from many locations, including several national parks.

Notes — 1. Monanthotaxis orophila belongs to a group of species with a large leafy bract. It can be distinguished from the other species by the leathery leaves, the 25–34 stamens, the hairy carpels, and by seeds longer than 12 mm.

2. Monanthotaxis germainii was regarded as distinct from M. orophila based on a number of characters by Boutique (1951b), however all characters show overlap, therefore the two names are synonymised. Only the number of stamens is slightly different between the lowland specimens (1200–1600 m above sea level) and the specimens from higher altitudes (1800– 2700 m). The 2 lowland specimens have 24–25 stamens, while the highland specimens have 27–33 stamens.Also the number of carpels which according to Boutique was 15–17 for M. germainii and 7–10 for M. orophila overlap, almost all flowers which the first author opened had 11–14 carpels. We have not seen flowers with 7–10 carpels as mentioned by Boutique (1951a) and Verdcourt (1971a).

Figures

Map 36 Distribution of Monanthotaxis orophila (Boutique) Verdc. (■) and M. parvifolia (Oliv.) Verdc. (●, O means uncertain dets).