Acalypha pedemontana 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 : 163

Acalypha pedemontana Cardiel & I.Montero sp. nov. ( Figs. 3 ).

Diagnosis:— Acalypha pedemontana Cardiel & I.Montero is morphologically close to A. hassleriana Chodat (1905: 606) but it differs from the latter in having stipules 2–3 mm long (vs c. 10 mm long), glandular hairs only on veins of the leaf blade (vs on the entire surface), leaf margin with triangular, acute teeth (vs rounded teeth), and female bracts with glandular trichomes only (vs glandular trichomes mixed with simple hairs).

Type:— BOLIVIA. Santa Cruz: Provincia Cordillera, along highway from Camiri to Abapó , 4.4 km N of school in Tatarenda Viejo , 8.2 km S of center of Tatarenda Nuevo , 790 m, 9º10´35´´S 63º29´47´´W, 18 April 2007, M. Nee & S. R. Hill 55110 (holotype MA [MA894276]!; isotypes LPB, MO [6427751]!, NY). (Figs. 2,4A) .

Description:— Shrub or subshrub c. 1 m high, monoecious; young branches thin, densely pubescent, with simple, slender, erect hairs to 0.1 cm long, mixed with conspicuous glandular hairs to 0.08 cm long; older branches slightly glabrescent. Stipules linear-lanceolate, c. 0.2 cm long, acute, hispidulous, promptly caduceus. Petiole 1.5–2.5(–4.5) cm long, with indumentum similar to that found on the young branches. Leaf blade 6.0–7.5 × 3.5–5.0(–7.0) cm, ovate-lanceolate, membranaceous; the base cordate; the apex acuminate, acumen mucronate, callose in edge; leaf margin dentate, teeth triangular, acute, with minute stellate crystalliferous papillae in margin; upper and lower surface pubescent with simple, thin, erect hairs, mixed with some sparse glandular trichomes limited to the veins only; venation prominent on lower surface, palmate to pinnipalmate, with 3–5 basal veins and 5–6 veins per side; stipels absent. Inflorescences unisexual. Male inflorescences axillary, to 8.5 cm long, spicate; peduncle to 2 cm long, with indumentum similar to that found on the young branches; rachis hidden by the flowers; flowers densely glomerate; bracts minute, c. 0.05 cm long, linear, ciliate–hispidulous. Female inflorescences terminal, erect, to 12 cm long, spicate; peduncle to 0.5 cm long, appressed pubescent; rachis clearly visible, appressed-pubescent. At fruiting stage female bracts are up to 0.7 cm long; margin divided into 10 linear-lanceolate teeth of c. ¾ of the bract length, with conspicuous, patent, glandular trichomes up to 0.07 cm long, mixed with simple, sparse hairs at the base, and covered by minute stellate crystalliferous papillae mainly in margin, flowers solitary. Male flowers inconspicuous; pedicel to 0.05 cm long, subglabrous, buds c. 0.05 cm diameter, subglabrous, papillose at the apex. Female flowers sessile; sepals 3, slightly joined at the base, triangular, c. 0.05 cm long, ciliated; ovary c. 0.1 cm diameter, densely hispid, with long hyaline hairs to 0.05 cm long; styles c. 0.5 cm long, free, thickened and papillose at the base, each divided into 6–7 slender segments. Capsule to 0.3 cm diameter, hispidulous in upper half; seeds ovoid, 0.18 × 0.12 cm, minutely foveolate. Allomorphic female flowers present at the apex of some female inflorescence; pedicels to 0.5 cm; sepals 3, regular; ovary cylindrical, bilaterally symmetrical, fimbriate at the ends, puberulous; styles not seen.

Distribution and habitat: — Bolivia. Acalypha pedemontana is only known from one collection made at the foot of the eastern slope of the Cordillera Oriental, in Santa Cruz Department, in Bolivia, at 790 m. It was collected by the roadside amongst bushes of Cnidoscolus cnicodendron Grisebach (1879:53) , in the former Chaco forest once dominated by Schinopsis marginata Engler (1883: 464) .

Etymology: —The epithet refers to the geographic location of the type specimen’s habitat, i.e. the foothill of the Cordillera Oriental of the Bolivian Andes.

Conservation status: —Notes on the specimen label do not indicate frequency or abundance of this species at the site. Thus, the status of this species can only be provisionally classified as Data Deficient (DD). This part of the Cordillera Oriental is highly disturbed and the original vegetation is now almost extinct, so it is probable this new species faces a high level of threat or it could be now extinct.

Figures

FIGURE 3. Acalypha pedemontana A. Flowering branch. B. Detail of the foliar node and stipules. C. Detail of the leaf upper surface. D. Detail of the leaf lower surface. E. Female bract (at fruiting stage). F. Calyx of female flower. G. Ovary and styles. H. Capsule. I. Seed. J. Allomorphic female flower. Illustrations by Iris Montero, from the holotype and the isotype of MA.