A new species of Barleria (Acanthaceae), its morphotaxonomy, cytogenetics and phylogenetic placement

Abstract

A new species, Barleria lavaniana (Acanthaceae), is described and illustrated. It resembles B. longiflora but differs from it in the characters of calyx, stamen, style and stigma. Stem anatomy reveals that vessel elements are mostly angular with a short tail at one end and a long tail on the other end. Xylem rays are usually biseriate and xylem fibres relatively thin-walled. Interxylary phloem is generally characterized by a single companion cell. The somatic chromosome number was 2n = 2x = 40. The karyotype is moderately symmetrical and fell in Stebbins’ 3b category. Chromosomes have median and submedian region centromeres. Based on cpDNA data, the new species is placed in subgenus Barleria and shows phylogenetic affinity towards B. longiflora and B. acuminata. Our findings suggest the need for comprehensive phylogenetic analyses of the genus Barleria based on high-throughput sequencing data to understand species interrelationships and biogeography.