Acalypha mayottensis I.Montero & Cardiel

Muñoz, Iris Montero, Levin, Geoffrey A. & Cardiel, José María, 2023, Monograph of Acalypha L. (Euphorbiaceae) of the Western Indian Ocean Region, with the description of a new species from Mayotte, Adansonia (3) 45 (26), pp. 395-496 : 461

34. Acalypha mayottensis I.Montero & Cardiel

PhytoKeys 140: 65 ( Montero Muñoz et al. 2020b). — Type: May - otte. Mamoudzou commune, îlot M’bouzi, 12°48’50”S, 45°14’08”E, 10-50 m, 22.XI.2000, J.-N. Labat, F. Barthelat, C.M. Hladik & A.B. Sifary 3268 (holo-, G[G00034240]; iso-, K, MAO, MO[MO-2965774], P[P00209719]). — Paratypes: Mayotte. Mamoudzou commune, îlot M’Bouzi, 12°48’57”S, 45°14’06”E, 90 m, 22.XI.2000, J.-N. Labat, F. Barthelat, C.M. Hladik & A.B. Sifary 3272 (G[G00034255], K, MAO, MO[MO-2966248], P[P00209724, P00209725]); îlot M’Bouzi, 12°48’39”S, 45°14’06”E, 26.XII.2002, F. Barthelat, A. de Vanssay & G. Rembert 1112 ( MAO, P[P00339165]). — Precise location unknown, probably from M’Bouzi islet, 01.I.2010, G. Viscardi 310 ( HKM, P[P02439826]) .

ICONOGRAPHY. — Montero Muñoz et al. (2020b); Figs 54F ; 57E.

ETYMOLOGY. — The epithet refers to Mayotte island, to which the small Mbouzi islet belongs, and to which this species appears to be endemic.

DISTRIBUTION AND HABITAT. — Endemic to Comoros Archipelago ( Mayotte). Dry forest and secondary forest. Altitudinal range 10- 90 m ( Fig. 53 ).

PRELIMINARY CONSERVATION ASSESSMENT. — Acalypha mayottensis is only known from Mbouzi islet. Its EOO and AOO are estimated to be 8 km 2. Mbouzi islet was declared a “Réserve Naturelle Nationale” in 2007, a category IV protected area ( Dudley 2008). In the 1990s the islet had lost 70% of its original forests to agriculture. Mbouzi now conserves 10% of its natural and secondary forest. Currently, the most serious threat are invasive species, both animals, such as Eulemur fulvus , and plants, such as Antigonon leptopus , Lantana strigocamara , Leucaena leucocephala , Litsea glutinosa , Spathodea campanulata and Furcraea foetida ( Boullet & Traclet 2018; Quintard et al. 2019). Due to its restricted geographic range and the threats from alien species, A. mayottensis is assigned a preliminary conservation status of Critically Endangered: CR B2ab(ii,iii).

MATERIAL EXAMINED. — 4 collections. Mayotte. Barthelat, F. 1112 ( MAO, P[P00339165]); Labat, J.-N. 3268 (G[G00034240], K, MAO, MO[MO-2965774], P[P00209719]), 3272 (G[G00034255], K, MAO, MO[MO-2966248], P[P00209724, P00209725]); Viscardi, G. 310 (P[P02439826]).

DESCRIPTION

Shrubs, deciduous, to 5 m tall, monoecious. Branches laxly pubescent with simple, erect trichomes to 1 mm long, glabrous when mature. Axillary buds ovoid, to 3 × 2.3 mm, perulate, perules 2, imbricate, chartaceous, blackish, glabrous. Stipules to 6 mm long, linear to triangular-lanceolate, becoming filiform when mature, margins scarious, sparsely hairy, glabrescent, and with some glands. Petioles slender, (2-)3-5(-6) cm long, pubescent with simple, curved, antrorse trichomes. Leaf blades 5-10 × 3-6 cm, ovate-lanceolate to elliptic-lanceolate, membranous; base rounded to subcordate; apex subacuminate to acuminate, acumen to 15 mm long, rounded; margin crenulate-serrulate to subentire, slightly revolute, teeth rounded; upper surface pubescent with simple, thin, erect trichomes, glabrescent; lower surface indumentum similar to that on upper surface but denser; axils of secondary veins with minute, sparsely hairy, pocket-shaped domatia, sometimes with hair-tuft domatia; margins ciliate in sinuses; venation actinodromous, basal veins 3, secondary veins 4-6 per side. Stipels absent. Inflorescences spiciform androgynous, axillary, to 6 cm long, mostly male with short female segment; peduncle thick, to 15 mm long, laxly pubescent with trichomes similar to those on young branches, glabrescent. Female segment to 2.5 cm long; bracts 1-2, sessile, enlarging in fruit to 19 × 21 mm, subreniform, veins and margin sparsely hairy with simple, erect trichomes to 1.5 mm long, glabrescent; margin crenate to subentire, sometimes dentate in young bracts, central tooth not prominent; bracteoles absent. Male segment persistent, to 4 cm long; flowers glomerate; bracts to 0.5 mm long, triangular, sparsely hairy. Male flowers: pedicel to 1 mm long, glabrous; buds to 0.7 mm diameter, sparsely hairy with simple, arachnoid trichomes. Female flowers 1 per bract, sessile; sepals 3[4], to 0.7 mm long, ovate-triangular, sparsely hairy with simple, arachnoid trichomes; ovary c. 1 mm diameter, 3-lobed, echinate, projections and surface hispid; styles 3, to 3 mm long, distinct, rachis thick, appressed-pubescent, each divided into 8-10 segments. Allomorphic flowers not seen. Capsules to 4 mm diameter, erinaceous projections conical, subacute, to 1 mm long, they and surface hispid with simple, erect trichomes to 1 mm long. Seeds 2.5 × 2 mm, pyriform, minutely foveolate.

Figures

FIG. 54. — A, B, Acalypha integrifolia Willd. (photo by J. M. Sarrailh); C, D, A. leptomyura Baill. (photo by T. Randrianarivony, T. Randrianarivony 749); E, A. marginata (Poir.) Spreng. (photo by F. Duban); F, A. mayottensis I.Montero & Cardiel (photo by J.-N. Labat, J.-N. Labat 3268); G, H, A. medibracteata Radcl.-Sm. & Govaerts (photo by L. Gillespie, L. Gillespie 10828).

FIG. 57. — Mature female bracts: A, Acalypha leptomyura Baill. (J.-N. Labat & T. Deroin 2320); B, A. levinii I.Montero & Cardiel (L. Gillespie 10809); C, A. linearifolia Leandri (G. Cours 4638); D, A. magistri I.Montero & Cardiel (D. Ravelonarivo 273); E, A. mayottensis I.Montero & Cardiel (J.-N. Labat, F. Barthelat, C.M. Hladik & A.B. Sifary 3272); F, A. medibracteata Radcl.-Sm. & Govaerts (R. Decary 16103); G, A. menavody (Leandri) I.Montero & Cardiel (M. Bardot-Vaucoulon 1016); H, A. nusbaumeri I.Montero & Cardiel (L. Nusbaumer LN1169). Illustration by Iris Montero Muñoz. Scale bars: A, C, D, F, H, 1 mm; B, E, G, 2 mm.

FIG. 53. — Distribution map of Acalypha mayottensis I.Montero & Cardiel in Comoros Archipelago.