Monanthotaxis glabra 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 : 159-161

33. Monanthotaxis glabra P.H.Hoekstra , sp. nov. — Fig. 14 ; Plate 3e ; Map 22

Monanthotaxis glabra is the only species of Monanthotaxis with both the outer and inner petals entirely glabrous.Additionally,it can be distinguished by the almost entirely glabrous young branches, the many stamens in three or four whorls and 11–20 carpels with 6 or 7 ovules per carpel. — Type: R. Demange 2830 (holo P ( P01982488 ); iso P01982489 ), Mali, Sikasso, Kléla , galerie du Lotio, 14 July 1965. Paratypes : L. Aké Assi et al. 4049 ( FR), Burkina Faso, Comoé, Banfora, Ouangolodou,à 10 km de Ouangolodougou,en allant vers Folonzo , 371 m, 20 Oct. 2007 ; L. Aké Assi 4933 ( G), Ivory Coast, Bouna, Ouango-Fitini , au bord de la Comoe, 13 July 1958 ; J. Bokdam 2865 ( BR, K, WAG), Ivory Coast, Bouna , 47 km S of Bavé, 20 June 1968 ; J.­ P. Essou & Agbani 1516 ( BENIN not seen, MO, WAG), Benin, Mono, Lokossa ,Aguida- houé, 19 Feb. 1999 ; J. B. Hall & Swaine GC 46214 ( GC not seen, K), Ghana, Brong-Ahafo Region, Bui by Black Volta , 24 July 1976 ; C. C. H. Jongkind et al. 7965 ( BR, G, K, MA, MO, P, WAG), Guinea, Nzérékoré, Nimba Mountains , Gba valley , 625 m, 14 July 2007 ; A. Le Thomas & Deroin 11 ( P), Ivory Coast, Grands-Ponts, N’Douci , station de la Lamto, 6 July 1985 ; C. Versteegh & den Outer 536 ( WAG), Ivory Coast, Korhogo, 50 km SE of Korhogo, at river Bandama-Blanc , 17 July 1969 .

Etymology. This species is named M. glabra as it is the only species of

Monanthotaxis with glabrous petals and sepals.

Shrub or liana, to 4 m long and 4 cm diam; young branches reddish brown, glabrous or sparsely covered with few whitish hairs c. 0.2 mm long; old branches reddish brown. Leaves: petiole 2.5–5 mm long, 0.7–1 mm diam, grooved, glabrous or sparsely covered with appressed hairs; lamina oblong-elliptic to obovate or narrowly so, 2.9–10.5 by 1.4–3.9 cm, 1.7–3.3 times longer than wide, chartaceous, not punctate, glabrous above, below sparsely covered with appressed, reddish brown hairs c. 0.2 mm long, becoming glabrous, base rounded or slightly subcordate or cuneate, glands hardly visible, apex rounded to acute, secondary veins 7–10 per side, curving upwards, tertiary venation hardly visible, slightly reticulate to percurrent. Inflorescences extra-axillary or terminal, composed of solitary flowers; sympodial rachis absent; pedicels 28–52 mm long, 0.3–0.5 mm diam, fruiting pedicels 0.6–1.1 mm diam, glabrous or sparsely covered with short hairs; lower bract absent; upper bract halfway up the pedicel or absent, lanceolate, c. 0.5 by 0.2 mm or just a tuft of yellowish hairs; flower buds globose. Flowers bisexual; sepals free, shallowly triangular, c. 0.7 by 1.6 mm, apex acute, glabrous; receptacle c. 2.3 mm diam, slightly convex; petals colour in vivo unknown, 6, in two whorls, outer petals broadly ovate, c. 8.6 by 8.5 mm, glabrous, inner petals elliptic, 6.5–7.5 by 3.3–3.5 mm, glabrous; stamens 50–80, in three or four whorls, free, obovoid-obconical, 2–2.2 mm long, filaments 0.4–0.7 mm long, thecae latrorse in young buds to extrorse, connective hiding thecae, papillate, staminodes absent; carpels 11–20, subcylindric, 3.4–3.5 by 0.6–0.7 mm, densely hairy, ovules 6 or 7, lateral, stigma elongate, 0.7– 0.8 mm long, glabrous. Monocarps 6– 20, red-brown, narrowly ellipsoid, 13–46 by 4–5 mm, densely to sparsely covered with appressed, yellowish brown hairs, apex rounded or apiculate, apiculum 0 – 2 mm long, stipes 4 – 5 mm long, slightly grooved. Seeds 1–7, ellipsoid, 6–7 by c. 4 mm, tawny brown, ends flattened, raphe not visible.

Distribution — Guinea, Liberia, Ivory Coast, Mali, Burkina Faso, Ghana, Benin.

Habitat & Ecology — In gallery forest and dense humid semi-deciduous forest. Altitude: 371– 625 m. Flowering: June, July; fruiting: May to July.

Preliminary IUCN conservation status — Vulnerable (VU): B2ab(iii). EOO: 353 482 km 2, AOO: 36 km 2. Monanthotaxis glabra is known from 9 collections and 8 locations of which 4 in protected areas. The other areas are under severe threat of deforestation and habitat degradation.

Note — Monanthotaxis glabra differs from all species of Monanthotaxis by the glabrous petals and sepals. The specimens had originally been identified as M. parvifolia ; however, that species has a subcordate leaf base, young branches densely covered with short hairs and very different flowers with stamens only in two whorls, hairy sepals and petals and glabrous carpels and fruits.

Figures

Plate 3 a. Monanthotaxis discrepantinervia Verdc. Flowering branch. — b. Monanthotaxis enghiana (Diels) P.H.Hoekstra. Leaves. — c. Monanthotaxis filamentosa (Diels) Verdc. Flower. — d. Monanthotaxis foliosa (Engl. & Diels) Verdc. Flowering branch. — e. Monanthotaxis glabra P.H.Hoekstra.Leaves and fruit. — f. Monanthotaxis hirsuta (Benth.) P.H.Hoekstra. Flowers (a: Couvreur 94; b: not collected; c: Letouzey 14591; d: Couvreur 601; e: Jongkind 7965; f: Jongkind 8836). — Photos: a, d: T.L.P. Couvreur; b, e–f: C.C.H. Jongkind; c: P.H. Hoekstra.

Map 22 Distribution of Monanthotaxis glabra P.H.Hoekstra (■, D means uncertain det) and M. gracilis (Hook.f.) P.H.Hoekstra (●).

Fig. 14 Monanthotaxis glabra P.H.Hoekstra. a. Fruiting branch; b. flower bud; c. flower bud with two outer and two inner petals removed; d. outer petal, inside view; e. inner petal, inside view; f. carpel; g. stamen, side and front view (a: Versteegh 536, WAG; b–g: Demange 2830, P). — Drawing by E. Winkel.