Acalypha richardiana Baill., 1661

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 : 473-474

43. Acalypha richardiana Baill.

Adansonia, recueil d’observations botaniques 1: 268 ( Baillon 1861).— Type: Comoros. Mohéli, “Île Mohilla”, s.d., M. Richard 287 (lecto-, designated by Montero Muñoz et al. [2018a: 108]: P[P04779566]; isolecto-, P[P04779562, P04779564, P04779565]). — Former syntypes: Madagascar. s.l., s.d., M. Richard 544 (P[P04779563]). — Mayotte. s.l., s.d., L. H. Boivin 3373 (GDC[G00324505], P[P00196299, P00196300], W[WRchb. 1889-0166704]).

Acalypha ovalifolia Baill. , Adansonia, recueil d’observations botaniques 1: 269 ( Baillon 1861). — Acalypha reticulata var. ovalifolia (Baill.) Müll.Arg. , Linnaea 34: 32 ( Müller Argoviensis 1865). — Acalypha filiformis var. ovalifolia (Baill.) Govaerts, World Checklist and Bibliography of Euphorbiaceae (and Pandaceae ) 62 ( Govaerts et al. 2000). — Type: Mayotte. XI.1848, L. H. Boivin 3372 (holo-, P[P00196298]).

ICONOGRAPHY. — Fig. 65G.

ETYMOLOGY. — The epithet honors French botanist Jean Michel

Claude Richard (1787-1868).

DISTRIBUTION AND HABITAT. — Endemic to the Comoros Archipelago (Anjouan, Moheli and Mayotte). Dry forest and secondary forest. Altitudinal range 20-680 m ( Fig. 64 ).

PRELIMINARY CONSERVATION ASSESSMENT. — Acalypha richardiana is only known from the Comoros. Its EOO is estimated to be 4 395 km 2 and its AOO 36 km 2, which is less than the 500 km 2 threshold of the B2 subcriterion of the Endangered category (see assessment of A. chibomboa from Comoros). We predict that ongoing habitat loss and the impact of alien species in this archipelago will cause continued decline of its EOO and AOO, so A. richardiana is assessed as Endangered (EN): EN B1ab(i,iii,iv) + B2ab(ii,iii,iv). MATERIAL EXAMINED. — 15 collections. Comoros Archipelago. Barthelat, F. 680 (P[P00273174, P00273175]), 1163 (P[P00437836]); Boivin, L.H. 3372 (P[P00196298]), 3373 (G[G00034250, G00324505], P[P00196299, P00196300, P02712256, P02712257], W[WRchb.1889-0166704]), s.n. (P[P00196291]); d’Alleizette,Ch. s.n. (L[L0242103]); Hildebrandt, J.M. 1661 (BREM[BREM_0001789], L[L0242104], P[P00635340]); Labat, J.-N. 2908 (P[P00078905]); Pascal, O. 954 (P[P00144572]); Richard, M. 224 (P[P04779560, P04779561]), 287 (P[P04779562, P04779564, P04779565, P04779566]), 544 (P[P04779563]), s.n. (P[P00196297]); Rouhan, G. 845 (P[P00684849]); Tinguy, H. 1001 (P[P00144571]).

REFERENCES. — Müller Argoviensis (1866: 852 as A. reticulata var. ovalifolia , 855); Baillon (1892: 1004); Palacký (1907: 25 as A. ovalifolia , 26); Voeltzkow (1917: 447); Pax & Hoffmann (1924: 127); Leandri (1942: 272); Govaerts et al. (2000: 62, 85, 105); Montero Muñoz et al. (2018a: 109).

DESCRIPTION

Shrubs, leaf persistence unknown, to 2 m tall, monoecious. Branches densely pubescent with simple, short, curved trichomes, glabrous when mature. Axillary buds spherical, to 1 mm diameter, perulate, perules 2, valvate, membranous, brownish, pubescent with simple, short trichomes. Stipules to 6 mm long, linear, sparsely hairy. Petioles 2-6(-9) cm long, indumentum similar to that on young branches. Leaf blades 7-13.5 × 2-7.5 cm, ovate-lanceolate, membranous; base rounded to truncate; apex acute to acuminate, acumen to 15 mm long, rounded, mucronate; margin crenate to crenate-dentate, slightly revolute, teeth rounded; upper surface laxly pubescent with simple, short, trichomes, denser on veins, glabrescent; lower surface subvelutinous, glabrescent; venation actinodromous, basal veins 3 or 5, secondary veins 5-8 per side. Stipels glandular, to 0.2 mm long, sparsely hairy. Inflorescences spiciform, androgynous, and sometimes solitary female bracts, axillary. Androgynous inflorescences to 6 cm long, mostly male with 1 female bract; peduncle to 2.5 mm long, it and rachis sparsely hairy. Female segment: bract 1, sessile, enlarging in fruit to 7 × 6 mm, suborbicular, pubescent; margin usually subentire, sometimes slightly crenate, with some sessile glands; bracteoles absent. Male segment persistent, filiform, laxly flowered, to 5.5 cm long; flowers glomerate; bracts to 0.8 mm long, triangular, sparsely hairy and ciliate. Solitary female bracts sessile, similar to those of androgynous inflorescences. Male flowers: pedicel to 0.5 mm long, sparsely hairy; buds to 0.5 mm diameter, sparsely hairy. Female flowers 1-2 per bract, sessile; sepals 3, to 0.5 mm long, triangular, glabrous, margin with some sessile glands; ovary c. 1 mm diameter, 3-lobed, apparently smooth, surface densely hispid with hyaline trichomes to 1 mm long; styles 3, to 4 mm long, distinct, sparsely hairy, each divided into 10-12 segments. Allomorphic flowers sometimes present, axillary; pedicel filiform, to 19 mm long, pubescent with simple, short, curved trichomes; sepals 3, to 0.5 mm long, triangular, ciliate and with some sessile glands; ovary 1-lobed, to 1 mm diameter, echinate, pubescent with simple, flattened trichomes; style 1, to 3 mm long, sparsely hairy. Capsules to 2 mm diameter, papillose-hispid, papillae acute, to 0.5 mm long, surface pubescent with simple, short trichomes. Seeds c. 1.5 mm diameter, subglobose, minutely foveolate.

NOTE

The specimens indicated as isolectotypes do not have Richard’s original labels. They instead have labels with Baillon’s handwriting giving the location as “ Madagascar ”. We believe that the correct location is the one indicated on the selected lectotype, “Île Mohilla” (currently named Mohéli), in the Comoros Archipelago. A search of specimens at P showed that Richard’s collections numbered 284-286, 288, 290, 291 and 293 are also from Mohéli (289 has no locality and 292 is not listed). Richard 544 has an apparently original label showing the locality only as “ Madagascar.” Collections at P with nearby numbers are labelled as being from either “Nord de Madagascar ” or “Île Nos-bé” (now Nossi-bé), so this collection could be from northern Madagascar, although we have seen no other specimens from outside the Comoros Archipelago .

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. 64. — Distribution map ofAcalypha richardiana Baill.in Comoros Archipelago.