Acalypha gracilipes Baill., 2054

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 : 439-440

18. Acalypha gracilipes Baill.

Adansonia, recueil d’observations botaniques 1: 273 ( Baillon 1861). — Acalypha commersoniana var. gracilipes (Baill.) Müll.Arg. , Prodromus Systematis Naturalis Regni Vegetabilis 15 (2): 850 ( Müller Argoviensis 1866). — Acalypha integrifolia var. gracilipes (Baill.) Pax & K.Hoffm., Das Pflanzenreich (Engler) 147, 16 (Heft 85): 106 ( Pax & Hoffmann 1924). — Type: Madagascar. s.l., s.d., P. Commerson s.n. (holo-, P[P 04022747]).

Acalypha reticulata var. cloiselana Leandri, Notulae Systematicae. Herbier du Muséum de Paris. Phanérogramie. Paris 10: 266 ( Leandri 1942). — Type: Madagascar. s.l., s.d., P. Commerson s.n. (lecto-, designated by Montero Muñoz et al. [2018a: 98]: P[P00513166]. — Former syntypes: Madagascar. Prov. Toamasina, Fénérive, H. Perrier de la Bâthie 9707 (P[P00513169]); Prov. Toliara, Fort Dauphin, J. Cloisel 156 (P[P00513165]); Forêt de Manantantely,

H. Humbert 5835 (P[P00513167, P00513168]); Fort Dauphin, G. F. Scott-Elliot 2493 (P[P00513171]); s.l., s.d., R. Baron 5980 (P[P00513164]); R. Baron 6420 (P[P00324562]).

Acalypha cloiselana Denis ex Leandri, Notulae Systematicae. Herbier du Muséum de Paris. Phanérogramie. Paris 10: 266 ( Leandri 1942) nom. nud. as synonym of A. reticulata var. cloiselana Leandri.

Acalypha commersonii Baill. ex Leandri, Notulae Systematicae. Herbier du Muséum de Paris. Phanérogramie. Paris 10: 266 ( Leandri 1942) nom. nud. as synonym of A. reticulata var. cloiselana Leandri.

ICONOGRAPHY. — Leandri (1942: 267); Fig. 35F.

ETYMOLOGY. — The epithet is taken from the Latin words ‘ gracilis ’, slender or delicate; and ‘ pes ’, foot. It probably refers to the slender and flexuous branches of this species.

DISTRIBUTION AND HABITAT. — Endemic to Madagascar (Analanjirofo, Alaotra-Mangoro, Atsinanana, Vatovavy-Fitovinany, Atsimo-Atsinanana, and Anosy). Littoral forest. On sandstone and unconsolidated sand. Altitudinal range (3-) 10-400 m ( Fig. 33 ).

PRELIMINARY CONSERVATION ASSESSMENT. — The EOO of Acalypha gracilipes is estimated to be 33 167 km 2, close to the threshold of the B1 subcriterion of the Vulnerable category, and its AOO 64 km 2, which is less than the 500 km 2 threshold of the B2 subcriterion of the Endangered category. This species grows mainly in littoral forests on sand. Due to their low elevation and subsequent easy accessibility, littoral forests are under constant pressure and are regarded as the most threatened vegetation zone in Madagascar ( Bollen & Donati 2006; Andriamandimbiarisoa et al. 2015). This species has been collected in some protected areas, but it is also known from several unprotected forests subject to constant pressure. We predict that ongoing habitat loss will cause continued decline of its EOO and AOO. Acalypha gracilipes 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. — 29 collections. Madagascar: Baron, R. 1391 (K), 5980 (P[P00513164]), 6420 (P[P00324562]); Commerson, P. s.n. (P[P00513166]), s.n. (P[P 04022747]), s.n. (P[P05604465]); Dorr, L.J. 4463 (K, MO, P[P00508455]); Dumetz, N. 764 ( MO [MO-2965758], P[P04779867]); Faliniaina, L. 9 (K, MO); Hoffmann, P. 279 (K); Humbert , H. 5835 (P[P00513167, P00513168]); Jussieu, A. s.n. (P[P04804753]); Leandri, J. 4296 (P[P04804743]); McPherson, G. 14325 ( MO [MO-2965762]), s.n. (P[P04804702]); Miller, J.S. 10464 (K, MO[MO-2966182], P[P05547263]); Perrier de la Bâthie, H. 9707 (P[P00513169]); Rabenantoandro, J. 1553 (P[P05481907]), 1580 ( MO [MO-3025022], P[P05481889]); Rabevohitra, R. 2054 ( MO [MO-2965759]); Raharimampionona, J. 38 (P[P05481876]); Rajeriarison, Ch. EUPH-26 (P[P04804488]); Ratovoson, F. 1752 ( MAUAM, MO[MO-2966280], P, TAN), 1941 ( MAUAM, MO[MO-2966287], TAN); Razakamalala, R. 6897 ( MO [MO-2965737], TAN); Rogers, Z.S. 901 ( MO [MO-2965730], P,TAN); Schatz, G.E. 2745 (K, P[P00508422]), 3436 (K, MO[MO-2966191], P[P00508420]); Scott-Elliot, G.F. 2493 (K, P[P00513171]) .

REFERENCES. — Müller Argoviensis (1866: 850) as A. commersoniana var. gracilipes ; Baillon (1892: 1004); Palacký (1907: 25); Pax & Hoffmann (1924: 106) as A. integrifolia var. gracilipes ; Govaerts et al. (2000: 69, 100); Montero Muñoz et al. (2018a: 98).

DESCRIPTION

Sprawling shrubs, leaf persistence unknown, to 4 m tall, monoecious. Branches flexuous, glabrous. Axillary buds spherical, to 0.5 mm diameter, perulate, perules 2, valvate, membranous, glabrous, light brown, margin with some sessile glands. Stipules to 1.2 mm long, triangular, slightly fleshy, sparsely hairy, margin papillate. Petioles canaliculate, (0.4-)0.7-1.4(-1.7) cm long, glabrous. Leaf blades (4-)5-7(- 7.5) × 1.5-2 cm, elliptic-lanceolate, chartaceous; base acute to cuneate; apex acuminate, acumen to 1.3 mm long, rounded to subacute, mucronate; margin crenate-serrate to subentire, slightly revolute, sometimes reddish, teeth obtuse; upper and lower surfaces glabrous; venation pinnate, secondary veins 5-7 per side. Stipels absent. Inflorescences spiciform, axillary, androgynous and male. Androgynous inflorescences to 5 cm long, mostly male with 1 female bract; sessile; rachis glabrous. Female segment: bract 1, sessile, enlarging in fruit to 3 × 4 mm, reniform, glabrous; margin dentate, slightly thickened, teeth c. 10, rounded, central tooth not prominent; bracteoles absent. Male segment persistent, to 4.5 cm long; flowers glomerate; bracts to 0.7 mm long, triangular-lanceolate, sparsely hairy with some simple, short trichomes at apex. Male inflorescences filiform, to 10 cm long; peduncle to 7 mm long, glabrous; bracts and bracteoles like those on androgynous inflorescences. Male flowers: pedicel to 0.5 mm long, glabrous; buds to 0.5 mm diameter, glabrous. Female flowers 1 per bract, sessile; sepals 3, to 0.5 mm long, triangular, glabrous; ovary c. 1 mm diameter, 3-lobed, papillose-hispid, papillae to 0.5 mm long, ending in simple, short trichome, surface glabrous; styles 3, to 5 mm long, slightly connate at base, rachis thick, glabrous, each divided into c. 15 segments. Allomorphic flowers not seen. Capsules to 2 mm diameter (immature), papillose-hispid, papillae to 0.5 mm long ending in simple, short trichome, surface glabrous. Seeds too young to describe.

NOTES

1) Acalypha gracilipes has been usually treated as a variety of A. integrifolia (or its synonym, A. commersoniana Baill. ex Müll. Arg. ) or as a variety of A. reticulata (for which the correct name is A. filiformis ), both of which are endemics of Mascarene Islands, but A. gracilipes can be clearly distinguished from these species by its denticulate female bracts and glabrous ovary and capsule surfaces, vs entire female bracts and hairy ovary and capsule surfaces in A. filiformis and A. integrifolia ; 2) Acalypha gracilipes can be distinguished from both A. urophylla and A. pervilleana mainly by its glabrous leaves with crenate to subdentate margins and obtuse to subacute apices, glabrous female bracts, and papillose-hispid and glabrous ovaries vs pubescent leaves with serrate margins and acuminate ( A. urophylla ) or usually caudate ( A. pervilleana ) apex, pubescent female bracts, and hispidulous ovaries with long papillae. In addition, the female bracts of A. pervilleana have a prominent central tooth, which is absent in both A. gracilipes and A. urophylla ; and 3) Leandri (1942) included the collection H. Perrier de la Bâthie 9746 as Acalypha reticulata var. cloiselana Leandri , which we treat as a synonym of A. gracilipes ; however, the specimen of this collection in P (P00513170) corresponds to A. urophylla .

Figures

FIG. 35. — Mature female bracts: A, Acalypha decaryana Leandri (R. Decary 2985); B, A. emirnensis Baill. (G. McPherson 14590); C, A. filiformis Poir. (P. Commerson s.n.); D, A. fimbriata Schumach. & Thonn. (J. Audru 40466); E, A. gillespieae G.A.Levin & I.Montero (L. Gillespie et al. 10692); F, A. gracilipes Baill. (R. Rabevohitra 2054); G, A. humbertii Leandri (W. Kaudern 222). Illustration by Iris Montero Muñoz. Scale bars: A, C-G, 1 mm; B, 2 mm.

FIG. 33. — Distribution map of Acalypha gracilipes Baill. in Madagascar.