Acalypha inselbergensis Cardiel & I.Montero, 2018

Cardiel, José María, Muñoz, Iris Montero & García, Irene Sancho, 2018, Three new species of Acalypha (Euphorbiaceae, Acalyphoideae) from Argentina, Bolivia, Brazil and Paraguay, Phytotaxa 356 (2), pp. 158-166 : 162-163

Acalypha inselbergensis Cardiel & I.Montero sp. nov. ( Fig. 2 ).

Diagnosis:— Acalypha inselbergensis Cardiel & I.Montero is morphologically close to A. amblyodonta (Müller Argoviensis) Müller Argoviensis (1874: 365) , but it differs from the latter in having female bracts with entire margin (vs dentate margin) and with a shiny exudate covering almost all the plant (vs none).

Type:— BRASIL. Pernambuco: Municipio Brejo da Madre de Deus, rock outcrop at the north shore of the Sitio Oítis dam, 560 m, 08º05.306´S, 36º22.909´W, 16 December 1999. L. Krause & A. Liebig 276 (holotype RB [RB00752960S]!; isotypes LZ, PEUFR, ROST, S [S11-29219]!) .

Description:— Shrub to 2 m high, monoecious; branches, leaves and inflorescences covered by a shiny exudate, not sticky to the touch in dry specimens; young and older branches thin, glabrous, with minute papillae, and lenticels sparse. Stipules lanceolate, to 0.3 cm long, acute, with minute hairs at margin, papillose-denticulate, caduceus. Petiole thin, 2.0–2.5(–3.0) cm long, glabrous, papillose. Leaf blade 5.5–6.5 × 2.0– 2.5 cm, ovate-lanceolate to triangularlanceolate, thin-membranaceous; the base rounded to sub-cordate; the apex acuminate with acumen sub-acute, callous at apex; the margin dentate, teeth rounded, callous in edge; upper and lower surface sub-glabrous, with some sparse hairs on veins, and minutely papillose with some papillae stained red; venation pinnipalmate, with 3 basal veins, and 7–9 veins per side; stipels absent. Inflorescences axillary, to 5 cm long, androgynous, with the male flowers in upper position and female flowers in lower position, separated from the male flowers by a nude segment of rachis to 0.5 cm long; peduncle 0.1–0.2 cm long, pubescent, with thin, arachnoid hairs, which extend to the rachis. Male part of the inflorescences to 3 cm long, spicate; flowers glomerate; bracts minute, to 0.05 cm long, triangular-oblong, obtuse at apex, papillae. Female part of the inflorescences to 1.0– 1.5 cm long, with 2 (3) bracts. At fruiting stage the bracts are 6 × 4 mm, suborbicular, glabrous; margin entire, with minute papillae; flowers 1–2. Male flowers inconspicuous; pedicel to 0.05 cm long, buds c. 0.05 cm diameter, with some sparse hairs. Female flowers sessile; sepals 3, slightly joined at the base, triangular, c. 0.05 cm long, papillae; ovary c. 0.1 cm diameter, glabrous, papillae; styles to 0.5 cm long, free, glabrous, each divided in the upper half into 7–9 slender segments. In the apex of some inflorescences appear solitary pedicellate and ebracteate female flowers. Capsule to 0.02 cm diameter, hispidulous and glandulose-papillae; seeds piriform, 0.12 × 0.10 cm, minutely foveolate.

Distribution and habitat:— Brazil. Acalypha inselbergensis is only known from a single collection from the northeast of Pernambuco state in Brazil. This specimen was growing on a granitic rock outcrops, at 560 m., in a soil filled rock depression within a shrubs community. This area contains some remains of Atlantic Forest biome.

Etymology: —The epithet refers to the unique habitat where this plant grows; which are known as inselberg. These are isolated hills or mountains that rise abruptly from a plain.

Conservation status: —Notes on the specimen label do not indicate local frequency or abundance of this species. Therefore we provisionally classified this species as Data Deficient (DD). Further surveys will be urgently needed to secure the survival of this species as well as the Atlantic Forest of northeast Brazil, which is one of the most threatened habitats in the Americas. Many species in this habitat are rare or classified as extremely endangered ( Gomes & Sobral-Leite 2013).

Figures

FIGURE 2. Acalypha inselbergensis. A. Flowering branch. B. Detail of the floral node and stipules. C. Detail of the leaf upper surface and margin. D, E. Details of the female part of the inflorescence. F. Calyx of female flower. G. Ovary and styles. H. Capsule. I. Seed. Illustrations by Iris Montero, from the holotype and isotype of S.