Acalypha radula Baker

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 : 471-473

42. Acalypha radula Baker

Journal of the Linnean Society. Botany. London 20: 254 ( Baker 1883). — Type: Madagascar: “ Central Madagascar ”, 1882, R. Baron 1818 (lecto-, designated here: K[K000186509]; isolecto-, P[P00513119, P00513120]).

Acalypha hildebrandtii Baill. , Bulletin mensuel de la Société linnéenne de Paris 2: 1005, 1180 ( Baillon 1892). — Type: Madagascar. Prov. Fianarantsoa, “Betsileo, Nandahizana”, J. M. Hildebrandt 3900 (lecto-, designated here: P[P00513121]; isolecto-, BREM[BREM_0001783], G[G00074184, G00190630], JE[JE00000288, JE00000289], K[K000186507], M[M0110604], P[P00513122]).

Acalypha salviifolia Baill., Étude générale du Groupe de Euphorbiacées 443 ( Baillon 1858), nom. nud.

Tragia salviaefolia Boj. ex Baill., Étude générale du Groupe de Euphorbiacées 443 ( Baillon 1858), nom. nud.

ICONOGRAPHY. — Baillon (1891: pl. 193); Figs 65F ; 69D.

ETYMOLOGY. — The epithet is taken from the Latin word ‘radula’, scraper, probably in reference to the rough appearance of the leaf surface.

DISTRIBUTION AND HABITAT. — Endemic to Madagascar (Alaotra-Mangoro, Analamanga, Itasy, Vakinankaratra, Amoron’i Mania, and Haute Matsiatra). Sclerophyllous woodlands and secondary forest. On basement rocks. Altitudinal range (800-) 1500-2000 m ( Fig. 63 ). PRELIMINARY CONSERVATION ASSESSMENT. — The EOO of Acalypha radula is estimated to be 33 908 km 2 and its AOO 60 km 2, which is less than the 500 km 2 threshold of the B2 subcriterion of the Endangered category. This species grows in the sclerophyllous woodlands in the highlands (see assessment of A. leptomyura ). This species has been collected in degraded forests and in unprotected areas, and in many localities. Its habitat is subject to various threats (uncontrolled fires for grazing and crops, charcoal production), so we predict that ongoing habitat loss and degradation will cause continued decline of its EOO and AOO. Acalypha radula is assessed as Near Threatened (NT) under criterion B. It meets the AOO values 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. — 28 collections. Madagascar. Anonymous 9628 (P[P00513109]); Anonymous s.n. (P[P00513097]); Baron, R. 272 (P[P00513096]), 1818 (K[K000186509], P[P00513119, P00513120]), 4068 (K[K000384473]); Benoist, M.R. 244 (P[P00513098]); Bojer, W. s.n. (P[P00724168]); Bosser, M.J. 15133 (P[P04779790, P04779793]), 19481 (P[P04779797]); Catat, L.D.M. 413 (P[P00513099]); d’Alleizette, Ch. s.n. (L[L0242131]); Decary, R. 13008 (P[P00513100]); Gillespie, L. 10757 ( MO), 10758 ( MO); Hildebrandt, J.M. 3865 ( BREM [BREM_0001787], G[G00034245], P[P00513101, P00513102, P00513103]), 3900 ( BREM [BREM_0001783], G[G00074184, G00190630], JE[JE00000288, JE00000289], K[K000186507], M[M0110604], P[P00513121, P00513122]); Humbert , H. 4575 (P[P00513107]), 29970 (G, P[P05547266]); Jard.Bot.Tananarive 2528 (P[P00513106]), 4537 (P[P00513104, P00513105]); Le Myre de Villers, M. s.n. (P[P00513108]); Perrier de la Bâthie, H. 9672 (P[P00513110, P00513111]), 9862 (P[P00513116]), 13357 (P[P00513114, P00513115]); Razafimandimbison, S. 1359 (S[S16-50647]); Service Forestier Madagascar 45-SF (P[P00513112]), s.n. (P[P00513113]); Viguier, R. 1836 (P[P00513118]).

REFERENCES. — Baillon (1861: 268) as A. salviifolia ; Müller Argoviensis (1866: 889) as A. salviifolia ; Baillon (1891: 193); Baillon (1892: 1004) as A. salviifolia ; Baillon (1895a: 1180) as A. hildebrandtii ; Palacký (1907: 25) as A. hildebrandtii ; Palacký (1907: 26); Palacký (1907: 26) as A. salviifolia ; Pax & Hoffmann (1924: 102) as A. salviifolia ; Pax & Hoffmann (1924: 156) as A. hildebrandtii ; Leandri (1942: 278); Leandri (1952); Jenkins (1987: 347); Jenkins (1990: 408, 433); Govaerts et al. (2000: 67) as A. hildebrandtii ; Govaerts et al. (2000: 85, 86, 105) as A. salviifolia ; Schatz (2001: 142); Sagun et al. (2006: 124); Seebaluck et al. (2015: 149, 153); Montero Muñoz et al. (2018a: 108).

DESCRIPTION

Shrubs, evergreen, to 2.5 m tall, monoecious or dioecious. Branches densely pubescent with simple, short, more or less appressed trichomes and hyaline trichomes to 0.8 mm long, glabrescent when mature. Axillary buds ovoid, to 2 × 1.5 mm, perulate, perules 2, imbricate, chartaceous, blackish, pubescent with simple, short trichomes. Stipules to 8 mm long, triangular-lanceolate, midrib thick, margin scarious, appressed-pubescent, especially on midrib. Petioles 0.5-2.2(- 3) cm long, indumentum similar to that on young branches and with scattered short, glandular trichomes. Leaf blades conspicuously bullate, 6-10 × (1.5-)2-3(-3.5) cm, narrowly triangular-lanceolate to linear-lanceolate, subchartaceous; base rounded to truncate, sometimes subcordate; apex rounded to acute; margin serrate, teeth subacute, irregular; upper surface pubescent with simple, short, erect, trichomes on top of blisters and on main veins and scattered, short, glandular trichomes, denser on veins near base, and sometimes stellate or fasciculate trichomes; lower surface pubescent with simple, thin trichomes, denser on veins, and sometimes stellate or fasciculate trichomes; venation actinodromous, basal veins 5, secondary veins 6-10 per side. Stipels absent. Inflorescences spiciform, unisexual, axillary. Male inflorescences densely flowered, to 5 cm long; peduncle to 8 mm long, indumentum similar to that on young branches; flowers glomerate; bracts to 0.5 mm long, narrowly spatulate, sparsely hairy and ciliate with simple trichomes, and with short, glandular trichomes. Female inflorescences densely flowered, to 6 cm long; peduncle to 8 mm long, indumentum similar to that on young branches; bracts 4-9, sessile, enlarging in fruit to 12 × 14 mm, subtriangular-reniform, pubescent with simple, thin, erect, trichomes and thick, glandular trichomes to 1 mm long, ciliate; margin subentire to shallowly dentate; teeth c. 39, triangular, with glandular trichomes, central tooth not prominent; bracteoles to 1.5 mm long, triangular, pubescent with simple, short trichomes and ciliate. Male flowers: pedicel to 0.8 mm long, sparsely hairy; buds to 1 mm diameter, sparsely hairy. Female flowers 1 per bract, sessile; sepals 3, to 0.8 mm long, oblong-lanceolate, sparsely hairy and ciliate; ovary c. 1 mm diameter, 3-lobed, smooth, surface hispid with simple, short, erect trichomes, and with glandular trichomes; styles 3, to 5 mm long, slightly connate at base, sparsely hairy on rachis, each divided into 9-10 segments. Allomorphic flowers sometimes present at female inflorescence apex, occasionally at male inflorescence apex; pedicel filiform, to 20 mm long, sparsely hairy; ovary 1-lobed, to 3 mm diameter, puberulent with simple, short trichomes, distally fimbriate; style 1, to 1 mm long, glabrous. Capsules to 5 mm diameter, smooth, surface sparsely hairy with simple, short, erect trichomes and glandular trichomes to 1.3 mm long. Seeds c. 3 × 2 mm, pyriform, minutely foveolate.

NOTES

1) Baker designated R. Baron 1818 as the type specimen of Acalypha radula but did not indicate the herbarium. We found three specimens of this collection, designating the best preserved of them as the lectotype; and 2) Baillon designated J.M. Hildebrandt 3900 as the type of Acalypha hildebrandtii but did not indicate the herbarium. We found nine specimens of this collection, designating the best preserved of them as the lectotype.

Figures

FIG. 65. — Mature female bracts: A, Acalypha perrieri Leandri (R. Decary 15792); B, A. pervilleana Baill.(J. J. Floret 682); C, A. pervilleana (J. M. Hildebrandt 3356); D, A.poiretii Spreng.(L. Boivin s.n.); E, A. rabesahalana I.Montero & Cardiel (H.Humbert 32480); F, A. radula Baker (Service Forestier Madagascar 45-SF); G, A.richardiana Baill. (M. Richard 224); H, A. rottleroides Baill. (L. Nusbaumer LN2629). Illustration by Iris Montero Muñoz. Scale bars: A, D, E, G, H, 1 mm; B, C, F, 2 mm.

FIG. 69. — A, Acalypha nusbaumeri I.Montero & Cardiel (photo by L. Nusbaumer, L. Nusbaumer LN1169); B, A. pervilleana Baill. (photo by L. Gillespie,L. Gillespie 10649); C, A. perrieri Leandri (photo by L. Gillespie, L. Gillespie 10835); D, A. radula Baker (photo by L. Gillespie, L. Gillespie 10758); E, A. rottleroides Baill. (photo by L. Nusbaumer, L. Nusbaumer 1933); F, A. spachiana Baill. (photo by L. Gillespie, L. Gillespie 10856); G, A. tremula I.Montero & Cardiel (photo by R. Randrianaivo, R. Randrianaivo 1160); H, A. urophylla Boivin ex Baill. (photo by L. Nusbaumer, L. Nusbaumer LN1663).

FIG. 63. — Distribution map of Acalypha radula Baker in Madagascar.