Monanthotaxis schweinfurthii (Engl. & Diels) 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 : 195-196

64. Monanthotaxis schweinfurthii (Engl. & Diels) Verdc. — Map 40

Monanthotaxis schweinfurthii (Engl. & Diels) Verdc. (1971b) 27. — Popowia schweinfurthii Engl.& Diels (1901) 51. — Enneastemon schweinfurthii (Engl. & Diels) Robyns & Ghesq. (1933) 165. — Enneastemon schweinfurthii (Engl. & Diels) Robyns & Ghesq. var. schweinfurthii : Le Thomas (1969) 252. — Type: G.A. Schweinfurth 3157 (holo B100153043;iso K000198984), Democratic Republic of the Congo, Orientale, Dungu, Mbruole, Mar. 1870.

Shrub, scandent shrub or liana; young branches densely covered with appressed, yellowish brown hairs 0.1–0.2 mm long, becoming glabrous; old branches dark brown. Leaves: petiole 4–9 mm long, 1.2–1.7 mm diam, slightly grooved or terete, indument as on branches; lamina oblong-obovate to obovate or narrowly so, 6.9–18.4(–20.6) by 3.7–6.5(–7.6) cm, 1.9–2.7 times longer than wide, chartaceous, not punctate, glaucous below, above sparsely covered with appressed, whitish hairs 0.4–0.5 mm long, becoming glabrous, primary vein more densely covered with ascending to erect, yellowish brown hairs 0.2–0.3 mm long, below sparsely to densely covered with appressed, yellow-brown hairs 0.1–0.2 mm long, primary vein more densely hairy, base cuneate to rounded with thickened black margins, apex obtuse, acute to acuminate, acumen to 15 mm long, secondary veins 9–13 per side, slightly curving, tertiary venation percurrent, hardly visible. Inflorescences axillary, composed of a solitary flower to 2- (or 3-)flowered fascicle-like rhipidia; sympodial rachis absent or <1 mm long; pedicels 9–20 mm long, 0.3–0.4 mm diam, fruiting pedicels 15–25 mm long, 1–1.8 mm diam, sparsely to densely covered with appressed, yellow-brown hairs; lower bract absent; upper bract in the lower half of the pedicel, ovate, 0.4–0.5 by 0.3–0.4 mm, indument as on pedicel; flower buds globose. Flowers bisexual; sepals connate at the base, depressed ovate, 0.7–1.2 by 1.2–1.8 mm, apex acute to obtuse, densely covered with appressed, yellow-brown hairs, persistent in fruit; receptacle 1.3–1.5 mm diam, flat; petals colour in vivo unknown, 6, in two whorls, base of inner petals visible in bud, outer petals ovate to broadly ovate, 4–4.8 by 2.8–4.6 mm, outside and inside densely covered with appressed, white-brown, short hairs, base glabrous, inner petals rhombic to elliptic, 2–4.3 by 1–3.3 mm, outside and apical part of the inside densely covered with white-brown hairs; stamens 9, in one whorl, free, clavate, 1–1.7 mm long, filaments 0.6–1.3 mm long, thecae extrorse, connective truncate, slightly prolonged inward and outward, hiding the thecae, glabrous except sparsely hairy on the inside, staminodes absent; carpels 5 or 6, subcylindric, 1.5–1.9 by 0.5–0.6 mm, densely hairy, ovules 5 or 6, lateral, stigma elongate, 0.2–0.4 mm long, glabrous. Monocarps 1–4, colour in vivo unknown, moniliform, each part ellipsoid, 15–34 by 8–9 mm, slightly verrucose, densely covered with appressed, whitish yellow hairs, apiculate, apiculum 3–6 mm long, stipes 3.5–4.8 mm long. Seeds 1–6, ellipsoid to subglobose, c. 10 by 8.5 mm, ochre-brown, ends rounded, raphe visible.

Distribution — Central African Republic, South Sudan, Democratic Republic of the Congo.

Habitat & Ecology — In gallery forest, swamp forest, and semi-deciduous forest.Altitude: 200–1290 m. Flowering: March to May, October; fruiting: December to March, May, July, October.

Vernacular names — Central African Republic: Búgù-àndima (Zande name) (M. Buckner 120). Democratic Republic of the Congo: Amapupu (T.B. Hart 1545).

Preliminary IUCN conservation status — Least concern (LC). EOO: 383 894 km 2, AOO: 92 km 2. This species has a quite wide distribution and has been collected several times recently, including in some nature reserves.

Note — Monanthotaxis schweinfurthii belongs to the Monanthotaxis schweinfurthii complex ( Fig. 1 , clade B) and can be recognized by the combination of having 5 or 6 carpels per flower and yellow-brown indument on the stems and leaves. This combination of characters also occurs in the allopatric M. barteri from West-Africa, see the note under that species.

Figures

Map 40 Distribution of Monanthotaxis schweinfurthii (Engl. & Diels) Verdc. (■) and M. seretii (De Wild.) P.H.Hoekstra (●).

Fig. 1 Bayesian 50 % majority rule consensus tree of the genus Monanthotaxis. Asterisks at nodes indicate node support, i.e., *** Strong node support, ** moderate node support, * weak node support, see Hoekstra et al. (2018). The letters A to K with adjacent black bars indicate the clades. The triangles, circles and squares represent morphological characters of the species which are of some use to distinguis the clades. Green triangles = staminodes absent, red triangles = staminodes present. Green circles = petals in one whorl, red circles = petals in two whorls, yellow circles = petals in bud basally in one whorl, at the top outer petals overlapping the inner ones. Green squares = inflorescences extra-axillary or if cauliflorous also extra-axillary inflorescences present, red squares = inflorescences axillary, supra-axillary or cauliflorous, red and green squares = both extra-axillary and axillary inflorescences present.