Monanthotaxis quasilanceolata P.H.Hoekstra, 2021

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 : 193

62. Monanthotaxis quasilanceolata P.H.Hoekstra , sp. nov. — Fig. 26; Map 39

Monanthotaxis quasilanceolata can be distinguished from all species of Monanthotaxis by the 5–11 cm long slender pedicels in combination with a lanceoloid flower bud, lanceolate sepals and lanceolate petals. It is the only species of Monanthotaxis that has the connective of the stamens conically prolonged above the thecae. — Type: J.J.F.E.de Wilde 10971 (holo consisting of 2 sheets:WAG0232743,WAG0232744;iso BR0000013211448,K not seen, LBV, MO not seen), Gabon, Ogooué-Maritime, Rabi-Kounga, Rabi, Shell/ Gabon, just N of Airstrip, 30 m, 26 Jan. 1993. Paratype: M.F. de Carvalho 5371 (MA), Equatorial Guinée, Rio Muni, Litoral, Bata-Sendje,Estrada km 40, a jusante de ponte sobre o Río Benito, 10 July 1993.

Etymology. The name quasilanceolata refers to the lanceolate shape of bracts, sepals, petals and connectives in side view; however, the leaves are oblanceolate.

Liana, 6–10 m long; young branches dark brown to blackish, densely covered with erect, reddish brown hairs c. 1.5 mm long, becoming glabrous; old branches pale brown. Leaves: petiole 2–5 mm long, 0.7–1 mm diam, grooved, indument as on branches; lamina obovate to oblanceolate, 7.7–14.6 by 2.6–5.3 cm, 2.3–3 times longer than wide, chartaceous to subcoriaceous, not punctate, dull green above, pale glaucous below, above sparsely covered with appressed, white hairs c. 0.5 mm long, becoming glabrous, primary vein with a more dense indument and composed of erect hairs, below sparsely covered with erect, yellowish hairs 0.7–1 mm long, base subcordate, with thickened margins, apex acuminate, acumen to 25 mm long, secondary veins yellowish, 7–12 per side, curving upwards, tertiary venation percurrent. Inflorescences leaf-opposed, composed of solitary pendent flowers; sympodial rachis absent; flowering pedicels 50–112 mm long, 0.6–0.7 mm diam, fruiting pedicels to 2.3 mm diam, covered with erect, reddish brown hairs, becoming glabrous; lower bracts absent; upper bract halfway up the pedicel, lanceolate, 8.5–30 by 2.4– 10 mm, indument as on pedicel; flower buds lanceoloid. Flowers bisexual; sepals ovate to lanceolate, 8–16 by 4.3–6 mm, apex acute to slightly acuminate, densely covered with appressed, yellowish hairs 0.3–0.5 mm long, persistent in fruit; receptacle 2.5–3.5 mm diam, convex; petals greenish yellow, drying reddish brown, 6, in two whorls, outer petals lanceolate, 30–35 by 11–13 mm, outside sparsely covered with appressed, white hairs, inside densely covered with appressed, white hairs giving a grey appearance, base glabrous, inner petals lanceolate, 14.5–15 by c. 6 mm, outside sparsely covered with appressed, white hairs, inside glabrous except for a few white hairs at the apex and margins; stamens> 60, in four whorls, free, oblong, 1.7–2 mm long, filaments 0.1–0.4 mm long, thecae extrorse, inner thecae smaller than the outer ones, connective conical, prolonged on top of the thecae, 0.7–0.9 mm high, hiding thecae, glabrous, staminodes absent; carpels 13, subcylindric, 3.5–4 by 0.7–0.8 mm, densely covered with yellowish hairs, ovules 8, uniseriate, lateral, stigma ellipsoid, geniculate at insertion with ovary, c. 1 mm long, hairy. Monocarps 10, colour in vivo unknown, fusiform to cylindric,> 60 by 4–6 mm, constricted between the seeds, constrictions to 1 cm long, slightly verrucose, apex apiculate, apiculum 5–8 mm long, covered with erect, reddish brown hairs, more densely so on constrictions and stipe, stipes 15–30 mm long, slightly to strongly grooved, rugulose. Seeds> 2, narrowly subcylindric, 18–19 by 3.5–5 mm, apex apiculate, apiculum to 0.5 mm long, ochre-brown, raphe visible as a longitudinal furrow from base to apex on both sides, funiculus c. 3.7 by 1.5 mm conical.

Distribution — Equatorial Guinea ( Rio Muni Litoral), Gabon (Ogooué-Maritime).

Habitat & Ecology — In primary forest and in small swamp. Altitude: c. 30 m. Flowering: January, July; fruiting: July.

Preliminary IUCN conservation status — Endangered (EN): B2ab(iii). AOO: 8 km 2. This species has only been collected twice in unprotected areas.

Figures

Map 39 Distribution of Monanthotaxis quasilanceolata P.H.Hoekstra (■) and M. sterilis P.H.Hoekstra (●).