Taxonomía de Pachyanthus (Melastomataceae: Miconieae)

Abstract

Pachyanthus (Melastomataceae: Miconieae) is traditionally reconnized as a Caribbean genus of shrubs and small trees, mostly local Cuban endemics. Similar to most genera in Miconieae, its generic delimitations are still unclear. Nineteen species of Pachyanthus in a broad sense are recognized in this revision, nine of them as Pachyanthus s.str., which includes the nomenclatural type of the genus. Most of the species in Pachyanthus s.str. are endemic to Cuba; only one species is distributed in Central America (Honduras, Nicaragua, and Belice). The other ten taxa are treated as “incertae sedis”, because their phylogenetic relationships with Pachyanthus s.str. and the rest of genera in Miconieae are still unclear. A key with all taxa of Pachyanthus s.l. is given. The species of Pachyanthus s.str. can be distinguished from other groups in Miconieae by the following combination of characters: petals ovate to triangular-ovate to broadly obovate, with mostly sagittate or cordate to rounded bases that are conspicuously unguiculate; calyx lobes connate before anthesis, then separating into sepal-like segments; anthers straight, ovate to oblong, yellow, and without connective appendages or, if present, then inconspicuous and anthers dehiscing by small apical pores; and seeds numerous, 0.8–1.6 mm long, obpyramidal, with a smooth testa. Seventeen names are typified: P. angustifolius, P. brachylobus, P. cordifolius, P. discolor, P. glaber, P. lindmanii, P. mayarensis, P. monopleurus, P. ovatus, P. pedicellatus, P. poiretii, P. shaferii, P. tetramerus, P. wrightii, Miconia blancheana, M. lundelliana, and M. monocephala.