49. Acalypha wilkesiana Müll.Arg.

Prodromus Systematis Naturalis Regni Vegetabilis 15 (2): 817 (Müller Argoviensis 1866), nom. cons. prop. Ricinocarpus wilkesianus (Müll. Arg.) Kuntze, Revisio Generum Plantarum 2: 618 (Kuntze 1891). — Acalypha amentacea Roxb. subsp. wilkesiana (Müll.Arg.) Fosberg & Sachet, Smithsonian Contributions to Botany 45: 10 (Fosberg & Sachet 1980). —

Type: Fiji. “ in insulis Fidji ”, s.d., Wilkes Expedition s.n. (U.S. Expl. Exped. under Capt. Wilkes) (lecto-, designated in Cardiel et al. 2022a: G-DC [one specimen over two sheets: G00324021 and G00324022]; isolecto-, GH [GH00045512], K [K000959008], US [US00096423, US00096424]).

ICONOGRAPHY. — André & Bois (1907: 358); Fig. 73H.

ETYMOLOGY. — The epithet honors American naval officer and explorer Charles Wilkes (1798-1877).

DISTRIBUTION AND HABITAT. — Native to Melanesia. Widely cultivated as ornamental plant throughout the tropics. Cultivated species in Madagascar (Analamanga and Vakinankaratra), Mascarene Islands (La Réunion) and Seychelles (Mahé) (Fig. 74).

PRELIMINARY CONSERVATION ASSESSMENT. — Acalypha wilkesiana is a widespread cultivated ornamental but is not known in the wild. Is considered native of Melanesia but of unknown origin (Sagun et al. 2010). It sometimes is found along forest edges and roads. We assess this species as Least Concern (LC).

MATERIAL EXAMINED. — 8 collections. Madagascar. Anonymous 11 (P[P05546985]); Anonymous s.n. (P[P05546986]); d’Alleizette, Ch. 705 (P[P04779510]); Rotereau, L. s.n. (P[P05510219]).

La Réunion. Séverin 68 (P[P04779511]).

Seychelles. Jeffrey, C. 606 (K); Thomasset, H.P. s.n. (K).

REFERENCES. — Robertson (1989: 200); Montero Muñoz et al. (2018a: 112).

DESCRIPTION

Shrubs or small trees, probably evergreen, to 4 m tall, monoecious. Branches usually tomentose to substrigose, sometimes also hispid, glabrescent when mature. Axillary buds naked, hispid with simple, erect trichomes. Stipules to 7(-10) mm long, linear-lanceolate or filiform, sometimes broadened at base, appressed-pubescent. Petioles 1-4(-8) cm long, tomentose. Leaf blades usually variegated green, red, yellow, purple, or copper, 8-20 × 3-10(-13) cm, usually broadly ovate-lanceolate, sometimes elliptic or obovate-lanceolate, membranous; base broadly cuneate, obtuse, or rounded, sometimes decurrent; apex acuminate, sometimes abruptly so, acumen to 40 mm long, obtuse, mucronate; margin serrate to crenate-serrate, teeth obtuse, irregular; upper and lower surfaces subglabrous, appressed-pubescent on veins; venation actinodromous, basal veins 3 or 5, secondary veins 7-9 per side. Stipels absent. Inflorescences spiciform, unisexual, axillary. Male inflorescences to 25 cm long; peduncle to 15 mm long, velutinous; flowers glomerate; bracts to 1 mm long, elliptic, sparsely hairy. Female inflorescences to 10 cm long, densely flowered; peduncle to 40 mm long, pubescent with simple, curved trichomes; bracts to 16, sessile, enlarging in fruit to 9 × 11 mm, sparsely hairy; margin deeply dentate, teeth c. 15, to 1/2 bract length, triangular-lanceolate, central tooth prominent; bracteoles absent. Male flowers: pedicel to 1 mm long, sparsely hairy; buds to 1 mm diameter, sparsely hairy. Female flowers 1 per bract, sessile; sepals 3, to 1 mm long, elliptic-lanceolate, puberulent; ovary c. 1.3 mm diameter, 3-lobed, smooth, surface densely pubescent; styles 3, to 7 mm long, distinct, glabrous, each divided into 8-10 segments. Allomorphic flowers not seen. Capsules to 5 mm diameter, verrucose, surface densely pubescent. Seeds c. 2 mm diameter, globose, minutely foveolate.