Acalypha leandrii I.Montero & Cardiel, 2020

Montero-Munoz, Iris, Levin, Geoffrey A. & Cardiel, Jose M., 2020, Four new species of Acalypha L. (Euphorbiaceae, Acalyphoideae) from the West Indian Ocean Region, PhytoKeys 140, pp. 57-73 : 57

2. Acalypha leandrii I.Montero & Cardiel sp. nov.

Diagnosis.

Acalypha leandrii I.Montero & Cardiel is morphologically similar to A. radula Baker, but differs from it mainly by having leaf blades broadly ovate-lanceolate, not bullate, and petioles 2-8 cm long (vs. leaf blades usually narrowly triangular-lanceolate, bullate, and petioles 1.5-1.8 cm long), mature female bracts with entire margins (vs. mature female bracts with dentate margins), and capsules with simple trichomes (vs. capsules with simple and glandular trichomes).

Type.

Madagascar, Reg. Melaky [Prov. Mahajanga]: Antsalova, vers Ambodiriana (E. d’Antsalova), 18°40'0.12"S 44°43'59.879"E, 100-150 m, 06 Dec 1952, J. Leandri, R. Capuron & A. Razafindrakoto 2037 (holotype: P [P05547059!]). Fig. 3 .

Description.

Shrubs or subshrubs (probably sprawling or clambering) evergreen [height unknown], probably dioecious. Young branches densely pubescent, with short, simple, antrorsely curved trichomes; older branches glabrous. Stipules c. 7 mm long, oblong-lanceolate, with scarious margins and a central rib; midrib appressed-pubescent, margins ciliate with thin trichomes mixed with minute glands. Axillary buds ovoid, c. 2 × 1 mm, perules 2, valvate, membranous, pubescent with short, simple trichomes. Petioles 2-8 cm long, indumentum similar to that found on the young branches, glabrescent. Leaf blades 8-12 × (3.5-) 4.5-9 cm, broadly ovate-lanceolate, membranous; base rounded to cordate; margins serrate, teeth acute, slightly callose-edged; apex acuminate to caudate, acumen acute, c. 2.5 cm long, mucronate; both surfaces laxly pubescent with simple, erect trichomes, also with short, antrorsely curved trichomes on veins; venation actinodromous, prominent in both surfaces, with 3 or 5 veins at the base, secondary veins 7-9 per side. Stipels triangular, c. 0.7 mm long, ciliate, mixed with glandular trichomes. Inflorescences unisexual, axillary, in terminal nodes. Male inflorescences spiciform, c. 8 cm long, peduncle c. 2 cm long, indumentum similar to that found on the young branches. Female inflorescences spiciform, with up to 18 bracts, c. 8.5 cm long, peduncle c. 2.5 cm long, indumentum similar to that found on the young branches. Female bracts sessile, enlarging in fruit to 6 × 12 mm, subreniform, with prominent veins on adaxial surface, laxly pubescent with erect, simple trichomes and thick glandular trichomes c. 1 mm long; margins entire. Male flowers inconspicuous, pedicel c. 0.5 mm long, sparsely hairy; buds c. 0.7 mm diameter, glabrous, papillose. Female flowers solitary, sessile; sepals 3, slightly connate at base, c.1 mm long, oblong-lanceolate, ciliate with simple, erect trichomes c. 0.5 mm long; ovary 3-locular, c. 1 mm diameter, densely hispid; styles 3, c. 5 mm long, slightly connate at base, each divided into 5 slender segments, glabrous. Capsules c. 3 mm diam., papillose-hispid, with papillae c. 0.5 mm long, each ending in a simple, erect trichome c. 1 mm long. Seeds pyriform, c. 2 × 1.6 mm, minutely foveolate.

Distribution and habitat.

Acalypha leandrii is known from two localities in western Madagascar, in the area east of Antsalova. They are both from the karstic massif of Mesozoic limestones known as Tsingy de Bemaraha, in the Melaky Region. This region has dry climates, and the primary vegetation is dry deciduous forest ( Schatz 2000, Moat and Smith 2007, Goodman et al. 2018). The altitudinal range of A. leandrii is from 100 to 300 m. (Fig. 2 ).

Etymology.

The proposed epithet honors the French botanist Jacques Désiré Leandri (1903-1982). He worked extensively in the Euphorbiaceae family from Madagascar, including writing the last taxonomic treatment of Acalypha from the island, in which he described numerous new species ( Leandri 1942). Leandri collected the type specimen of this species.

Conservation status.

Acalypha leandrii is known from three collections. The extent of occurrence (EOO) could not be calculated. Its area of occupancy (AOO) is estimated to be 8 km2. The Tsingy de Bemaraha lies within a national park and a nature reserve that has been IUCN category II and Ia protected areas ( Dudley 2008, Goodman et al. 2018) since 1927 and a UNESCO World Heritage Site since 1990 ( Goodman et al. 2018). The forest of this area has local anthropogenic pressures such as fire associated with the renewal of zebu (cattle) pastures, logging for construction and deforestation for new agricultural lands. Bemaraha has lost more forest habitat from 2006 to 2016 compared to 1996 to 2006 ( Goodman et al. 2018). No specimens of this species have been collected for 60 years, so we cannot rule out that this species has become extirpated from one or both areas. In conclusion, due to habitat loss and the absence of recent collections, A. leandrii is assigned a preliminary IUCN conservation status of Critically Endangered: CR B2ab(ii,iii).

Additional specimen examined

(paratypes). Madagascar. Reg. Melaky [Prov. Mahajanga]: Calcaires de l’Antsingy, vers Andobo (E. d’Antsalova), en remontant vers Tsiandro, 18°40'0.12"S, 44°43'59.879"E, 05-08 Feb 1960, 300 m, J. Leandri & P. Saboureau 2996 (K!, P [P05543680!, P00324506!], MO [MO-3025001!], TAN); J. Leandri & P. Saboureau 3016 (G!, P [P05547274!], MO [MO-2966304!]).

Figures

Figure 2. Map of Madagascar and the Mayotte island showing the distributions of Acalypha gillespieae (square), A. leandrii (rhombus), A. mayottensis (triangle) and A. nusbaumeri (circle).

Figure 3. Acalypha leandrii A flowering female branch B flowering male branch C detail of node, stipules, and petiole base D detail of node with axillary bud E detail of upper leaf surface showing the leaf base and stipels F mature female bract G ovary and styles H calyx of the female flower I capsule J seed. Based on J. Leandri, R. Capuron & A. Razafindrakoto 2037 (A, C-J) and J. Leandri & P. Saboureau 2996 (B). Illustration by Iris Montero Munoz.