Four new species of Perilimnastes (Sonerileae, Melastomataceae) from Vietnam

Perilimnastes is a genus currently treated in the polyphyletic Phyllagathis. Recent phylogenomic analyses have identified a morphologically cohesive lineage referred to as the Phyllagathis (raphides) clade, which should be excluded from Phyllagathis and treated as a distinct genus under the name Perilimnastes. Morphological and phylogenomic data have confirmed that four new species collected from Vietnam are part of the Phyllagathis (raphides) clade. They are described herein as Perilimnastes multisepala, P. setipetiola, P. uniflora, and P. banaensis. Perilimnastes multisepala is phylogenetically closest to Phyllagathis setotheca, and morphologically to P. fruticosa and P. stenophylla, but is distinct in the 4- to 8-lobed calyx, 28 × 9 mm, apically long acuminate petals, and 1–2 mm pedicel at fruiting stage. Perilimnastes setipetiola, P. uniflora, and P. banaensis are phylogenetically most closely related. Perilimnastes uniflora is characterized by its prostrate habit, small size, glabrous, obovate to obovate-lanceolate leaf blade, and solitary flower. Perilimnastes setipetiola and P. banaensis resemble each other in habit, leaf size and shape, and sessile or near sessile inflorescences but can be easily distinguished by the indumentum of the stems and leaves.