Monanthotaxis komorensis P.H.Hoekstra, 2016

Hoekstra, Paul H., Wieringa, Jan J. & Chatrou, Lars W., 2016, A nonet of novel species of Monanthotaxis (Annonaceae) from around Africa, PhytoKeys 69, pp. 71-103 : 83-84

Monanthotaxis komorensis P.H.Hoekstra sp. nov. Figs 7 , 8

Type.

MAYOTTE, Grande Terre , Mont Combani, départ du GR menant au sommet, 10 January 2002, F. Barthelat 671 (holotype: P [P00273165!]; isotypes: G [G00404210!], K, MAYOT, MO [5735265!]) .

Diagnosis.

Differs from all other Monanthotaxis species in the combination of having solitary flowers on a short pedicel with 6 staminodes alternating with 6 stamens.

Description.

Liana or shrub to 2m; young branches dark reddish brown with ascending to slightly erect yellowish hairs 0.2 mm, old branches greyish brown to blackish brown, glabrescent with lenticels. Leaves: petioles 2-3(-4) × 1.4-1.6 mm, grooved adaxially, slightly more dense indumentum as branches; lamina 4.0-17.0 × 1.8-5.7 cm, length:width ratio 2.2-3.4, oblong to elliptic lanceolate, base subcordate, apex acute, chartaceous, discolorous, adaxially glossy green, abaxially glaucous, adaxially glabrous or with a few yellowish hairs at the base of the midrib, abaxially with scattered short ascending whitish yellowish hairs 0.1-0.3 mm, soon glabrescent, venation festooned brochidodromous, secondary veins (8-)13-18, from base curving upwards, tertiary venation reticulate, adaxially slightly raised. Inflorescences axillary, leaf-opposed or terminal, composed of a solitary flower; sympodial rachis reduced or wanting; flowering pedicels 3-6 × 0.4-0.5 mm with ascending to erect hairs 0.1-0.2 mm; lower bracts wanting; upper bracts halfway the pedicel, ovate to lanceolate, 0.3-0.8 × 0.4-0.5 mm; flower buds rounded to slightly ovate. Flowers bisexual; sepals 3, 0.6-0.8 × 1.4-1.6 mm, broadly ovate, with short yellowish hairs, apex obtuse; receptacle flat, 1.8-2.5 mm in diameter; petals 6 in two whorls, creamy yellow with pinkish to reddish brown base of the inner petals; outer petals 5.5-7.0 × 5.3-5.4 mm, ovate, outside with short yellowish appressed hairs, inside with very short hairs, but glabrous at base; inner petals 4.2-4.4 × 3.0-3.3 mm, rhombic, outside with short yellowish hairs, inside with very short hairs, but glabrous at base; stamens 6-7 in one whorl, free, obconic 1.2 mm, filaments 0.4 mm, anthers lateral to introrse, connective glabrous, truncate, prolonged inward, staminodes 6 alternating between the stamens, 0.7 mm, glabrous; carpels 8, 1.4-1.5 × 0.2 mm, subcylindric, densely hairy, with 2 lateral ovules, stigma elongate 0.6 mm, with a few hairs at base. Fruits: pedicels 9 × 0.9 mm; sepals persistent, slightly acrescent; stipes 2.0-2.5 mm; monocarps up to 7, ellipsoid with 1 or 2 seeds, 10-17 × 5-6 mm, slightly constricted between the seeds, apex rounded, glabrous or with a few short hairs, verrucose, ripe fruits red. Seeds 6 × 5 mm, ellipsoid, apex slightly apiculate, flattened were touching with other seed, ochre-brown, raphe slightly visible as a longitudinal furrow from base to apex, ruminations lamelliform.

Distribution.

Mayotte, Grande Terre and Mbouzi; Comoros, Anjouan. Figure 7 .

Ecology.

Not rare in humid and lowland hill forests, including secondary vegetation. It is also found in shady places in dry forest, especially along riversides.

Phenology.

Flowering from November to January, fruits collected in January and April.

Vernacular names.

Shibushi language: Fotsy ambadiki (F. Barthelat 590), Fotsy Ambadiky bé (F. Barthelat 1045), Fotsy ambadiky lahy (F. Barthelat 1045), Foutsi Ambadiki (O. Pascal 280), Sari langilangy (H. Ralimanana 277), Tchavadiki (O. Pascal 338).

Conservation status.

Proposed IUCN Red List Category: Vulnerable (VU): B2ab(I, ii, iii, iv), EOO (including Anjouan) 1231 km2, AOO 32 km2, 9 locations. This species has probably disappeared from the island Anjouan as the only collections were made more than 100 year ago, however there are 9 recent collections from Mayotte from different localities on the island Grande Terre of which some in nature reserves and one on Mbouzi, a protected island. The vegetation of the island Mayotte remains under threat, likely reducing the population of Monanthotaxis komorensis in the future.

Etymology.

Named after the Comoro Archipelago. Komorensis is written with a K as in the Latin script of the Comorian language and Shimaore.

Additional specimens examined (all paratypes).

COMOROS. Anjouan: Lavanchie 24 (P [P00213916]) and Lavanchie 25 (P [P00213917]) . MAYOTTE. Grande Terre: Mamoudzou , reserve forestière de Majimbini, 24 Jan 2001, F. Barthelat 269 (G [G00404208], K, MAYOT, MO, P [P00229255]); Mont Combani, 15 Nov 2001, F. Barthelat 590 (G [G00404209], K, MAYOT, MO [5730093], P [P00273086]); Tsararano, Tchaourembo, 17 Oct 2002, F. Barthelat 1045 (MAYOT, P [P00290506]); Mlima Combani, 28 Dec 1995, O. Pascal 280 (P [P00127022]); Dapani, 17 Jan 1996, O. Pascal 338 (P [P00127021]); Mlima Combani, 15 April 1996, O. Pascal 487 (G [G00404211], K, MO, P [P00127020]); Mont Combani, 12°57.44'S, 45°07.75'E, 16 Nov 2002, H. Ralimanana 277 (G [G00404207], K, MAYOT, P [P00538263], TAN); vallon à station pompage Ouroveni, 8 Nov 1989, H. Tinguy 1028 (P [P01987602]). Ilot MBouzi: 12°48.33'S, 45°14.00'E, 26 April 1999, M.M. Pignal 1285 (P [P00176736]) .

Discussion.

This is the only known species of Monanthotaxis on the Comoros and Mayotte. It is easily distinguished from almost all other Monanthotaxis species by having 6 staminodes alternating with 6 stamens, all in a single whorl. The only other species sharing that feature, viz. Monanthotaxis congoensis Baillon and Monanthotaxis paniculata P.H.Hoekstra are very different. These have a single whorl of petals (vs two whorls in Monanthotaxis komorensis ), inflorescences of raceme-like or panicle-like rhipidia, their young branches are densely covered with yellowish brown short hairs and they occur in Central Africa. The flowers of Monanthotaxis glaucocarpa (Baill.) Verdc., a species from Madagascar, are not known. This species differs from Monanthotaxis komorensis in having longer pedicels (>30 mm vs 9 mm), longer stipes (7-9 mm vs 2.0-2.5 mm) and longer and bigger seeds (12-15 mm vs 6 mm). Further, the leaves are less elongate and the young branches are glabrous.

Figures

Figure 7. Distribution map of Monanthotaxis filipes (red square) in Tanzania and Monanthotaxis komorensis (green circles) on the Comoros archipelago.

Figure 8. Monanthotaxis komorensis P. H. Hoekstra. A Photographs in the field of collection Barthelat 833 B-C idem, Barthelat 1045, D idem, Barthelat 1319. Photos: Fabien Barthelat.