Monanthotaxis mortehanii (De Wild.) 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 : 181-182

51. Monanthotaxis mortehanii (De Wild.) Verdc. — Map 33

Monanthotaxis mortehanii (De Wild.) Verdc.(1971b) 31. — Popowia mortehanii De Wild.(1914) 381. — Type: M.G. Mortehan 722 (holo BR0000008824073 ), Democratic Republic of the Congo, Equateur, Bumba, Dundusana, Nov. 1913.

Liana; young branches dark brown covered with erect, reddish brown hairs 0.05–0.1 mm long, soon becoming glabrous; old branches brown. Leaves: petiole 5–9 mm long, 2.4–2.9 mm diam, grooved, indument as on branches; lamina obovate, 15–23 by 8–10 cm, 1.9–2 times longer than wide, chartaceous, not punctate, glaucous below, above glabrous, below sparsely covered with appressed, yellowish to reddish brown hairs c. 0.1 mm long, veins with slightly more dense indument, base rounded to subcordate, with thickened black margin, apex acute to shortly acuminate, acumen to 1 mm long, secondary veins 12–15 per side, straight, tertiary venation percurrent.

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Plate 5 a–b. Monanthotaxis mcphersonii P.H.Hoekstra. a. Leaves above; b. leaves below. — c. Monanthotaxis montana (Engl. & Diels) P.H.Hoekstra. Flower bud. — d–f. Monanthotaxis paniculata P.H.Hoekstra. d. Leaves; e. inflorescence with fruits; f. fruit . — g. Monanthotaxis poggei Engl. & Diels. Flowering branch. — h. Monanthotaxis suffruticosa P.H.Hoekstra. Flowering branch (a–b: Couvreur 528; c: Couvreur 891; d–f: Couvreur 1108; g. photographed in Democratic Republic of the Congo, no specimen collected; h: LÖtter 1741). — Photos: a–b, d–f: T.L.P.Couvreur; c: P.H.Hoekstra; g: B.Würsten; h: M.C. Lötter.

♂ Inflorescences unknown. ♀ Inflorescences cauliflorous, condensed many-flowered glomerules or panicles to 6 cm long; sympodial rachis 2–3 cm long, covered with erect, reddish brown hairs 0.4–0.6 mm long; flowering pedicels 10–25 mm long, 0.8–1 mm diam, indument as on rachis; bracts broadly ovate, 1.5–1.8 by 1.5–1.8 mm, indument as on rachis; flower buds ovoid. ♀ Flowers: sepals free to slightly connate, broadly ovate to broadly triangular, c. 2.1 by 2.3 mm, densely covered with reddish brown hairs c. 0.1 mm long; receptacle c. 1.7 mm diam, convex; petals colour in vivo unknown, 6, in two whorls, free; outer petals broadly ovate, 6.1–6.2 by 6.1–6.3 mm, outside densely covered with reddish brown hairs c. 0.2 mm long, inside densely covered with yellowish papillae, inner petals spathulate, c. 1.8 by 0.9 mm, outside and inside densely covered with yellowish papillae; carpels c. 106, narrowly ellipsoid, 1.5–1.6 by 0.5–0.6 mm, densely hairy, ovules 6, lateral, stigma elongate, 0.4–0.5 mm long, slightly grooved at the apex, glabrous. Monocarps and seeds not seen.

Distribution — Democratic Republic of the Congo ( Equateur).

Habitat & Ecology — In forest. Flowering: November.

Preliminary IUCN conservation status — Critically endangered (CR): B2ab(iii). AOO: 4 km 2. This species is only known from one collection from more than 100 years ago.

Note — Monanthotaxis mortehanii is only known from the type specimen. It can be distinguished from other cauliflorous species of Monanthotaxis by the appressed, short hairs on the young branches, erect, long hairs on the pedicels and by having more than 100 carpels. Furthermore, it has wider leaves, longer and broader petioles than other species with unisexual flowers.