Acalypha medibracteata Radcl.

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 : 462-464

35. Acalypha medibracteata Radcl. -Sm. & Govaerts

Kew Bulletin 52 (2): 477 ( Radcliffe-Smith & Govaerts 1997). — Acalypha gagnepainii Leandri Notulae Systematicae.Herbier du Muséum de Paris. Phanérogramie. Paris 10: 274 ( Leandri 1942) nom. illeg., non A. gagnepainii Merr. ( Merrill 1938) . — Type: Madagascar.Prov. Toliara, Massif du Vohitsiombe (Fort-Dauphin), 31.VII.1926, R. Decary 4664 (lecto-, designated by Montero Muñoz et al. [2018a: 104]: P[P00508417]; isolecto-, S[S07-14667]). — Former syntypes: Madagascar. Prov. Toliara, Vallée du Mandrare, s.d., R. Decary 2620 (P[P00508418]); Vallée de l’Ikonda, au N d’Ambovombe, R. Decary 8913 (P[P00887487]); Imangory, s.d., R. Decary 8948 (P[P00508416]); Beteny (limite Nord-Est de l’Androy), 22.XI.1931, R. Decary 9355 (P[P00508415], G[G00034242], GB[GB0047682]).

Acalypha medibracteata var. calcicola (Leandri) Radcl. -Sm. & Govaerts, Kew Bulletin 52 (2): 477 ( Radcliffe-Smith & Govaerts 1997). — Acalypha gagnepainii var. calcicola Leandri, Notulae Systematicae. Herbier du Muséum de Paris. Phanérogramie. Paris 10: 275 ( Leandri 1942). — Type: Madagascar. Prov. Toliara, vallée moyenne du Mandrare près d’Anadabolava, X.1933, H. Humbert 12422 (lecto-, designated by Montero Muñoz et al. [2018a: 104]: P[P00508409]; isolecto-, P[P00508405, P00508406, P00508407, P00508408]). — Former syntypes: Madagascar. Prov. Toliara, Fort-Dauphin, J. Cloisel 18 (P[P00508410, P00508411]); Basse vallée du Fiherenana, s.d., H. Humbert 11573 (P[P00508412, P00508413]).

ICONOGRAPHY. — Leandri (1942: 269); Figs 54 G, H ; 57F.

ETYMOLOGY. — The epithet refers to the position of the female bracts near the middle of the bisexual inflorescences ( Radcliffe-Smith & Govaerts 1997).

DISTRIBUTION AND HABITAT. — Endemic to Madagascar (Menabe, Atsimo-Andrefana, Androy, and Anosy). Dry deciduous forest, dry spiny thickets, and sometimes in riparian forest. On basement rocks, Tertiary limestone, sandstone, and unconsolidated sand. Altitudinal range 100-800 m ( Fig. 55 ). PRELIMINARY CONSERVATION ASSESSMENT. — The EOO of Acalypha medibracteata is estimated to be 85 039 km2 and its AOO 92 km 2, which is less than the 500 km 2 threshold of the B2 subcriterion of the Endangered category. This species grows mainly in dry deciduous forests and spiny thickets (see assessment of A. decaryana ). The remaining original vegetation is still decreasing ( Moat & Smith 2007, Gautier et al. 2018). A. medibracteata has been collected in some protected areas, but it is also known from several unprotected forests subject to various threats (uncontrolled fires for grazing and crops, logging, mining, etc.). We predict that ongoing habitat loss will cause continued decline of its EOO and AOO. Acalypha medibracteata is assessed as Near Threatened (NT) because its AOO meets the threshold needed for a threatened category, but the number of locations is too high to meet the conditions required for a listing under the Endangered category.

MATERIAL EXAMINED. — 41 collections. Madagascar. Afzelius, K. s.n. (P[P05547249]); Baron, R. 646 (K, P[P04779782]); Bernardi, L. 11576 ( BR [BR0000021450181], G, P[P04779802]); Bosser, M.J. 3700 (P[P04779804]), 3726 (P[P04779807]), 3756 (P[P04779806]), 13871 (P[P04779812, P04779815]), 13950 (P[P04779817, P04779818]); Cloisel, J. 18 (P[P00508410, P00508411]); Decary, R. 2620 (P[P00508418]), 4664 (P[P00508417], S[S07-14667]), 8913 (L[L0241358], P[P00887487]), 8948 ( NY, P[P00508416]), 9355 (G[G00034242], GB[GB-0047682], P[P00508415]), 15956 (P[P05547255]), 15963 (P[P05547041]), 15970 (P[P05547232]), 16029 (P[P00324525, P05510102]), 16103 (P[P05547231]), 16123 (P[P05547233]), s.n. (L[L0241301]); Gillespie, L. 10828 ( MO); Goudot, J. 192 (G[G00420838]); Homolle, A.M. 1503 (P[P05547178]), 1504 (P[P05547226]); Humbert , H. 11573 (P[P00508412, P00508413]), 12422 (P[P00508405, P00508406, P00508407, P00508408, P00508409]), 19885 (P[P05547275, P05547276]), 29015 (P[P05547048]), 29467 (P[P04779860]); Lam, H.J. 5455 (L[L0241359], P[P00508414], WAG[WAG.1578538]); O’Connor, S. 22 (K); Phillipson, P.B.1750 (P[P04779820]), 2368 ( MO, P[P04779820], WAG[WAG.1578536]), 2447 ( MO, P[P04779819], WAG[WAG.1578537]), 2701 ( BR [BR0000016205871], P[P05547045]); Randrianasolo, A. 152 (P[P05547042]); Ravelonanahary 2770-RN (P[P05547046]), 4762-RN (P[P05547043, P05547044]); Ravelonarivo, D. 4643 ( MO [MO-3029388]); Sauther, M. 33 (P[P04779822]).

REFERENCES. — Govaerts et al. (2000: 75, 100); Montero Muñoz et al. (2018a: 105).

DESCRIPTION

Shrubs, deciduous, to 2 m tall, monoecious. Branches cinereous, nodose, pubescent with curved, antrorse trichomes, glabrescent when mature. Axillary buds ovoid, to 2 × 1.5 mm, perulate, perules 2, imbricate, chartaceous, light brown, woolly with simple, arachnoid trichomes. Stipules to 1.5 mm long, lanceolate, woolly with simple, arachnoid trichomes, base with some sessile glands. Petioles 0.5-1(-3.5) cm long,indumentum similar to that on young branches. Leaf blades 3.5-5(-7) × (0.5-)1-1.5(-2.5) cm, usually linear-lanceolate to oblong-lanceolate, sometimes ovate-lanceolate, membranous; base rounded; apex acute to subacuminate,acumen to 6 mm long, acute, mucronate; margin crenulate-serrulate, teeth with gland at apex; upper and lower surfaces laxly pubescent with simple, erect trichomes, and with simple, curved trichomes on veins, glabrescent; venation pinnate, secondary veins to 7-8 per side. Stipels glandular, to 0.2 mm diameter, glabrous. Inflorescences spiciform, androgynous, axillary, to 7.5 cm long; peduncle to 20 mm long, pubescent with simple, arachnoid trichomes. Female segment to 3.5 cm long; bracts 1-2(-3), sessile, enlarging in fruit to 12 × 10 mm, reniform, pubescent with short, simple trichomes and flattened, resinous glands, glabrescent; margin denticulate to subentire, central tooth not prominent; bracteoles absent. Male segment deciduous, to 2 cm long; flowers glomerate; bracts to 1.2 mm diameter, orbicular, woolly with simple, arachnoid trichomes, glabrescent; flowers glomerate, with stalked, flattened, resinous glands between pedicels. Male flowers: pedicel to 0.6 mm long, sparsely hairy; buds to 0.6 mm diameter, sparsely hairy. Female flowers 2 per bract, sessile; sepals 3, to 0.5 mm long, triangular, sparsely hairy; ovary c. 1 mm diameter,3-lobed, smooth, surface densely pubescent with simple, erect trichomes and flattened resinous glands; styles 3, to 5 mm long, distinct, sparsely hairy, each divided into c. 8 segments. Allomorphic flowers not seen. Capsules to 3 mm diameter, smooth, laxly pubescent with simple, short, curved trichomes and flattened resinous glands. Seeds c. 1.9 × 1.5 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. 55. — Distribution map of Acalypha medibracteata Radcl.-Sm.& Govaerts in Madagascar.