Friday, September 22, 2023

[Botany • 2022] Pleroma piranii (Melastomataceae: Melastomateae) • A New Species endemic to Southern Cadeia do Espinhaço, Minas Gerais, Brazil


Pleroma piranii F.S.Mey. & Almeda 

in Meyer, Pacifico et Almeda, 2022. 
 
Abstract
A new species of Pleroma, endemic to Southern Cadeia do Espinhaço in Minas Gerais, Brazil, is described. Pleroma piranii is morphologically similar to Pleroma velutinum but differs in having larger leaves 2.5 ̶ 7.1 × 1.4 ̶ 4.7 cm (vs. 2.4 ̶ 4.1 × 1.3 ̶ 2.1 cm in P. velutinum), that are densely sericeous on the adaxial surface (vs. moderately strigose), with 7 veins (vs. 5 veins), with obtuse to slightly cordate base (vs. obtuse base only), and completely glabrous style (vs. moderately beset with appressed white eglandular trichomes along much of their length). The distributions of these two species are allopatric; P. piranii occurs only in Minas Gerais, while P. velutinum occurs only in Bahia. According to our assessments based on IUCN criteria, P. piranii is Endangered (EN), because its occurrence is restricted, its populations are small, and most of them occur in unprotected areas. Here we present a description for this new species, taxonomic notes, a distribution map, a chromosome number count, illustration and photos, and a conservation assessment.

Keyswords: Chromosome number, Planalto de Diamantina, Serra do Cipó, Taxonomy, Tibouchina s.l.

 Pleroma piranii.
 A. Branch. B. Details of the trichomes that cover the branches. C. Leaf with obtuse base, abaxial surface. D. Leaf with obtuse base, adaxial surface. E. Details of the cordate base of the leaf (abaxial surface). F. Flower at anthesis in lateral view. G. Petal, abaxial surface. H. Antesepalous stamen. I. Antepetalous stamen. J. Hypanthium and calyx lobes in lateral view. K. Gynoecium. L. Bracteole with indumentum distributed only in the central portion of the abaxial surface, glabrous at the margin. M. Adaxial surface of the bracteole shown in L. N. Bracteole with indumentum distributed along the entire abaxial surface to the margin. O. Adaxial surface of the bracteole shown in N.
[A-D and F-O drawn based on Almeda et al. 7762 (CAS); E based on Almeda et al. 7762 (HUFU).]

 Photos of the inflorescence, flowers, and some floral parts of live specimens of  Pleroma piranii
 A. Partial inflorescence. B. Detail of androecium and gynoecium. C. Senescent flower, in the initial period of fruiting, without petals and stamens. D. Flowers with petals, stamens, and style.
Voucher: Almeda et al. 7762. (All photos by Frank Almeda).

Pleroma piranii F.S.Mey. & Almeda sp. nov.


Fabrício Schmitz Meyer, Ricardo Pacifico and Frank Almeda. 2022. A New Species of Pleroma (Melastomataceae: Melastomateae) endemic to Southern Cadeia do Espinhaço, Minas Gerais, Brazil. Phytotaxa. 560(1); 30-42. DOI: 10.11646/phytotaxa.560.1.2