Thursday, November 16, 2023

[Botany • 2023] Perilimnastes banaensis, P. multisepala, P. setipetiola & P. uniflora • Four New Species of Perilimnastes (Melastomataceae: Sonerileae) from Vietnam


Perilimnastes setipetiola J.H.Dai, T.V.Do & Ying Liu,
 P. uniflora J.H.Dai, T.V.Do & Ying Liu,

 Dai, Do et Liu, 2023.

Abstract
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.

Key words: Melastomataceae, Perilimnastes, Phyllagathis, taxonomy

Perilimnastes multisepala
 A habit B adaxial (top) and abaxial (bottom) leaf surfaces C close-up of a branchlet showing a 2-flowered cyme. 
A top view of a flower B longitudinal section of a flower showing the isomorphic stamens C top view of a young capsule D lateral view of a young capsule E top view of an old capsule F longitudinal section of an old capsule showing enlarged ovary crown and morphology of the placental column and placentas. 
Scale bars: 5 mm (B); 3 mm (F). 
All from Jin-hong Dai and Ying Liu 821 (A, PE, SYS).

 Perilimnastes multisepala J.H.Dai, T.V.Do & Ying Liu, sp. nov.

Etymology: The specific epithet is based on the 4–8 calyx lobes of this species.

Distribution: Perilimnastes multisepala is currently known from Đại Lộc, Quảng Nam Province, Vietnam (Fig. 1). It grows on rocks along streams in the forest, at 574 m elevation.

Perilimnastes setipetiola
A. habit B adaxial (top) and abaxial (bottom) leaf surfaces C a flowering branch D a branch showing hispid petioles and terminal and axillary infructescences E top view of a flower F longitudinal section of a flower showing the isomorphic stamens G longitudinal section of an old capsule showing enlarged ovary crown and morphology of the placental column and placentas.
 Scale bars: 5 mm (E, F); 3 mm (G). All from Jin-hong Dai and Ying Liu 836 (A, PE, SYS).

 Perilimnastes setipetiola J.H.Dai, T.V.Do & Ying Liu, sp. nov.

Etymology: The specific epithet is based on the stout long bristles on the petiole of this species.

Distribution: Perilimnastes setipetiola is currently known from Đà Lạt, Lâm Đồng Province, Vietnam (Fig. 1). It occurs at damp places in forests, at 1,500–1,700 m elevation.


  
 Perilimnastes uniflora J.H.Dai, T.V.Do & Ying Liu, sp. nov.
 
Etymology: The specific epithet is based on the solitary flowers of this species.

Distribution: Perilimnastes uniflora is currently only known from Ba Na Hills, Hòa Ninh, Đà Nẵng, Vietnam (Fig. 1). It occurs on damp rocks along streams in forests, at 1,360 m elevation.


 Perilimnastes banaensis J.H.Dai, T.V.Do & Ying Liu, sp. nov.


Jin-Hong Dai, Truong Van Do and Ying Liu. 2023. Four New Species of Perilimnastes (Sonerileae, Melastomataceae) from Vietnam. PhytoKeys. 235: 1-19. DOI: 10.3897/phytokeys.235.112133