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| Pleroma barbellatum P.J.F.Guim., D.Nunes & I.M.Araújo, in Guimaraes, Silva, Araújo et Romero, 2022. |
Abstract
Pleroma barbellatum P.J.F.Guim., D.Nunes & I.M.Araújo a new species of Melastomataceae (Melastomateae) from the Espinhaço Range of Minas Gerais State, Brazil, is described and illustrated, and their affinities and diagnostic characters are here discussed. Pleroma barbellatum is closely related to P. formosum, P. martiale, and P. riedelianum. They share a similar habit and leaves that are alike in size and shape. However, they can be distinguished by differences in the trichomes of the branches, leaves and inflorescences, in addition to other characters related to the type of inflorescence and size of the bracteoles. We recommend a conservation status of Endangered for P. barbellatum.
Keywords: Campos Rupestres, Diamantina Plateau, Espinhaço Meridional, Grão-Mogol, Melastomateae
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| Pleroma barbellatum P.J.F.Guim., D.Nunes & I.M.Araújo. (a) Flowering branch. (b) Barbellate trichomes on the branch. (c) Floral bud. (d) Outer surface of bracteole. (e) Inner surface of bracteole. (f) Flower with petals removed. (g) Petal. (h) Antesepalous stamen. (i) Detail of the trichomes on the filament. (j) Anther apex. (k) Flower in longitudinal section. From W.R. Anderson et al. 35497 (at RB). |
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| Environments and living specimens of Pleroma barbellatum P.J.F.Guim., D.Nunes & I.M.Araújo. (a) Rocky outcrop of campo rupestre in Biribiri State Park. (b) Steep rocky slopes with extensive outcrops in Biribiri State Park. (c) Flower. (d) Leaf blades and gall. (e) Detail of bracts. (f) Fruits. Living specimens from I.M. Araújo et al. 261. Photos: I.M. Araújo. |
Pleroma barbellatum P.J.F.Guim., D.Nunes & I.M.Araújo sp. nov.
Diagnosis: A shrub or tree 1–2 m or 2–3 m tall, is readily recognized by its barbellate and eglandular trichomes (on the branches, petioles, leaf blade surfaces, pedicels, bracts and bracteoles, hypanthia, outer surface and margins of sepals, and base of style), oblong, elliptic or lanceolate leaf blades 15–44 × 6.5–13.5 mm, with strigose indumentum on the adaxial surface, and obtuse, rounded or cuneate base, terminal cyme inflorescences 3–5 cm long with up to 5 flowers or flowers solitary and terminal, campanulate hypanthia covered by a strigose bristly indumentum, and ensiform sepals 4–6 × 1.5–2.5 mm. Pleroma barbellatum is similar to Pleroma formosum (Cogn.) P.J.F.Guim. & Michelang., but is readily distinguished by shorter leaf blades 15–44 mm long (versus 40–55 mm long in P. formosum), cyme inflorescences (vs. thyrsoids), 1–5 flowers per inflorescence (vs. 35–58 flowers per inflorescence), bracteoles 10–17.5 × 6.5–10 mm (vs. 4–6 × 1.4–2 mm), sepals 4–6 mm long (vs. 2.5–2 mm long).
Etymology: The specific epithet, barbellatum, refers to shortly barbed trichomes (see Beentje 2016) that are easily observed on branches, leaves, pedicels, bracts and bracteoles, hypanthia, outer surface and margins of sepals, and base of the style (see Figures 1B and 2).
Paulo José Fernandes Guimaraes, Diego Nunes Da Silva, Inara Montini Araújo and Rosana Romero. 2022. A New Species of Pleroma (Melastomataceae) from the Southern Espinhaço, Minas Gerais, Brazil. Webbia. Journal of Plant Taxonomy and Geography. 77(2); 247-256. DOI: 10.36253/jopt-13088
