Monanthotaxis latistamina P.H.Hoekstra

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 : 170-171

41. Monanthotaxis latistamina P.H.Hoekstra — Fig. 19 ; Plate 4a–c ; Map 23

Monanthotaxis latistamina P.H.Hoekstra in Hoekstra et al.(2016) 88. — Type: T.L.P. Couvreur 565 (holo consisting of 3 sheets: WAG.1577028, WAG. 1577029,WAG.1577030;iso LBV not seen,YA not seen), Gabon, Ogooué-Ivindo, Ivindo National Park, along main trail departing from behind the herbarium at the Research station of Ipassa , N0°30.23' E12°47.59', 519 m, 11 Nov. 2013.

Scandent shrub or liana, to 4 m long; young branches sparsely covered with appressed, yellowish hairs 0.1–0.2 mm long, soon becoming glabrous; old branches dark brown to blackish. Leaves: petiole 5–12 mm long, 1.3–1.7 mm diam, grooved, indument as on branches; lamina oblong-elliptic to obovate or narrowly so, 6–13 by 3.5–7.2 cm, 1.6–2.7 times longer than wide, chartaceous to subcoriaceous, punctate, although hardly visible in older leaves, green above, pale greyish green below, young leaves above and below sparsely covered with appressed hairs 0.1–0.2 mm long, soon becoming glabrous, base cuneate, rounded to subcordate with thickened black margin, apex acute to acuminate, acumen to 13 mm long, secondary veins 7–8(–10) per side, oblique, from base curving upwards, tertiary venation reticulate, raised above. Inflorescences axillary or terminal, solitary, in fascicle-like rhipidia or in to 4 cm long lax panicle-like, up to 6-flowered rhipidia; sympodial rachis from almost absent to at least 1 cm long, covered with appressed hairs to becoming glabrous; flowering pedicels 8–17 mm long, 0.3–0.4 mm diam, indument as on sympodial rachis; lower bracts strongly reduced or absent; upper bract placed halfway up the pedicel, ovate, 0.6–0.7 by 0.4–0.6 mm, indument as on rachis; flower buds globose to slightly ellipsoid. Flowers bisexual; sepals connate at the base, depressed ovate, 0.8–1 by 1.2–1.5 mm, apex obtuse to slightly acute, covered with appressed, yellowish, short hairs; receptacle 1.2–1.5 mm diam, flat; petals green when young, 6, in one whorl, outer petals overtopping inner petals in bud, elliptic to slightly ovate, with inwardly reflexed appendage at apex, 1.6–2.5 by 0.7–1.2 mm, outside papillate to covered with appressed, short hairs, inside papillate, most densely so at the apex; stamens 6, in one whorl, free, alternating with the petals, oblong, wider than thick 1–1.2 by 0.6–0.7 mm, radial width 0.2–0.3 mm, densely papillate, filaments c. 0.1 mm long, thecae extrorse, connective truncate to conical, densely papillate, staminodes absent; carpels 6–9, narrowly ellipsoid, 1–1.4 by 0.4–0.6 mm, densely covered with reddish brown hairs, ovules 6, lateral, stigma globose to slightly elongate, 0.1–0.2 mm long, grooved to almost bifurcate, glabrous. Monocarps and seeds not seen, but reported as yellowish.

Distribution — Gabon (Ogooué-Ivindo), Republic of the Congo (Niari).

Habitat & Ecology — In evergreen forest and forest on shallow soil at summit of hill. Altitude: 520–1020 m. Flowering: May, October, November.

Preliminary IUCN conservation status — Endangered (ED): B2ab(iii). EOO: 17 682 km 2, AOO: 16 km 2. Of the four collections of this species only one is from a protected area, while the other locations are under threat of logging and habitat destruction.

Note — Monanthotaxis latistamina closely resembles M. congolana , the only other species of Monanthotaxis with papillate petals and stamens. For the differences with M. congolana see note under that species.

Figures

Plate 4 a–c. Monanthotaxis latistamina P.H.Hoekstra.a.Leaves;b. inflorescence;c.flowers. — d.Monanthotaxis letouzeyi (Le Thomas) Verdc.Leaves. — e–f. Monanthotaxis mannii (Baill.) Verdc. e. Leaves; f. leaves and flower (a–c: Couvreur 565; d: Couvreur 752; e–f: Jongkind 11848). — Photos: a–d: T.L.P. Couvreur; e–f: C.C.H. Jongkind.

Fig. 19 Monanthotaxis latistamina P.H.Hoekstra. a. Flowering branch; b. flower bud; c. flower with 2 petals removed; d. outer petal, outside view; e. outer petal, inside view; f. stamen, side view; g. stamen inside view; h. carpel (all: Couvreur 565, WAG). — Drawing by E. Winkel.