Acalypha rottleroides Baill., 2629

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 : 474-476

44. Acalypha rottleroides Baill.

Adansonia, recueil d’observations botaniques 1: 270 ( Baillon 1861).— Type: Madagascar. Prov. Antsiranana: Nossibé, 1837, M. Richard 215 (holo-, P[P00536728]).

Acalypha polynema Baill., Histoire physique, naturelle et politique de Madagascar Atlas, 2, fasc. 27: t. 187 ( Baillon 1891). — Type: Madagascar. Baillon 1891: pl. 187, holotype.

Acalypha juliflora Pax, Botanische Jahrbücher für Systematik, Pflanzengeschichte und Pflanzengeographie. Leipzig 19: 95 ( Pax 1894). — Type : Madagascar. Prov. Antsiranana: Nossibé , “Urwald von Loko-bé”, XII.1879, J. M. Hildebrandt 3279 (lecto-, designated here: W[W1889-0089773]; isolecto-, JE[JE00004291], K[K000186527], P[P00536729, P00536730, P00536731]).

ICONOGRAPHY. — Baillon (1891: t. 185, t. 187); Figs 65H ; 69E.

ETYMOLOGY. — The epithet likely refers to a resemblance to the genus Rottlera Roxb. (now treated as a synonym of Mallotus Lour. ; Euphorbiaceae ).

DISTRIBUTION AND HABITAT. — Endemic to Madagascar (Diana and Sava). Degraded lowland evergreen moist forest and dry deciduous forest. On Mesozoic limestone and on basement rocks. Altitudinal range 200-370 m ( Fig. 66 ).

PRELIMINARY CONSERVATION ASSESSMENT. — The EOO of Acalypha rottleroides is estimated to be 5 643 km 2, which is near to the threshold of the Endangered category, and its AOO 32 km 2. It is known from only four locations. Acalypha rottleroides grows mainly in dry deciduous forest, but in Nosy Bé this species grows in lowland evergreen moist forest. The collections found in Nosy Bé were made in 1879 and this island has been largely deforested for conversion into coffee plantations, rice fields, ylang-ylang ( Cananga odorata Hook. ) orchards, and sugar cane fields ( Andreone et al. 2013). Currently, the area where these specimens were collected is the National Park of Lokobé (Category II; Dudley 2008). The remaining collections of A. rottleroides were made in Ankarana Special Reserve, Loky-Manambato, and in the unprotected forests of Ambilanivy and Rangoty (Ampasindava). These areas are threatened by mining (sapphire and gold), illegal cutting of precious woods, and fires to improve grazing and agriculture ( Kull 2000; Rakotondravony 2009; Goodman et al. 2018). Continued habitat loss leads us to assess A. rottleroides as Endangered: EN B2ab(ii,iii,iv).

SPECIMEN EXAMINED. — 8 collections. Madagascar. Cours, G. 5626 (P[P00324530]); Hildebrandt, J.M. 3279 (G, JE[JE00004291], K[K000186527], L[L0241761], P[P00536729, P00536730, P00536731], W[W1889-0089773]); Humbert , H. 19065 (P[P00324502]); Nusbaumer, L. LN 1933 (G[G00090298], P[P05547268]), LN 2629 (G[G00180763], P[P04786259]); Ranirison, P. PR 1085 (G[G00090513], P[P05547267]); Richard, M. 181 (P[P04779559]), 215 (P[P00536728]).

REFERENCES. — Müller Argoviensis (1866: 854); Baillon (1891: 182); Baillon (1895b: 1197); Baillon (1895b: 1197) as A. polynema ; Palacký (1907: 25) as A. juliflora ; Palacký (1907: 26) as A. polynema ; Palacký (1907: 26); Nitschke (1923: 280) as A. juliflora ; Pax & Hoffmann (1924: 127); Leandri (1942: 277); Govaerts et al. (2000: 70, 105) as A. juliflora ; Govaerts et al. (2000: 86); Montero Muñoz et al. (2018a: 109).

DESCRIPTION

Shrubs, deciduous, to 2 m tall, monoecious. Branches whitish, hispid with simple, hyaline trichomes to 2 mm long, and with glandular trichomes to 1.5 mm long, glabrescent when mature but glandular trichomes persistent. Axillary buds spherical, to 1 mm diameter, perulate, perules 4, overlapping (superposed), membranous, scarious, margin irregular, glabrous. Stipules to 7 mm long, ovate-lanceolate to oblong-lanceolate; margin scarious, glabrous except margin ciliate with some short, glandular trichomes. Petioles (3-)3.5-7.5(-8) cm long, indumentum similar to that on young branches, hyaline trichomes deciduous. Leaf blades 7-13 × 5-7.5 cm, ovate-lanceolate, thin-membranous; base cordate; apex acute to acuminate, acumen to 10 mm long; margin crenate to denticulate, teeth rounded to acute; upper and lower surfaces subglabrous, with some thin, glandular trichomes to 1.5 mm long; margin ciliate with simple, short trichomes, and with glandular trichomes to 1 mm long, venation actinodromous, basal veins 5, secondary veins 4-6 per side. Stipels absent. Inflorescences spiciform, androgynous, axillary, to 9 cm long, mostly female with short male segment (sometimes appearing female due to male segment falling); peduncle to 10 mm long, with glandular trichomes to 1 mm long. Female segment laxly flowered, to 8 cm long; bracts 6-9, sessile, enlarging in fruit to 6 × 9 mm, reniform, with glandular trichomes to 1.5 mm long; margin subentire to crenate, teeth triangular, central tooth not prominent; bracteoles absent. Male segment deciduous, to 1 cm long; flowers glomerate; bracts to 1.5 mm diameter, suborbicular, scarious, glabrous; margin irregular, papillose. 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 1.2 mm long, triangular-lanceolate, reddish, margin irregular, with sparse glandular trichomes; ovary c. 1 mm diameter, 3-lobed, smooth, surface with some glandular trichomes to 0.5 mm long; styles 3, to 6 mm long, slightly connate at base, glabrous, each divided into 9-10 segments. Allomorphic flowers not seen. Capsules to 2.5 mm diameter, smooth, surface with sparse glandular trichomes. Seeds c. 1.5 × 1.2 mm, pyriform, minutely foveolate.

NOTE

Baillon designated J. M. Hildebrandt 3279 as the type of Acalypha juliflora but did not indicate the herbarium. We found six 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. 66. — Distribution map of Acalypha rottleroides Baill. in Madagascar.