The bushviolets and porcupine flowers — a revised infrageneric classification and species checklist for Barleria (Acanthaceae)

Summary Barleria is a species-rich genus of Acanthaceae (Acanthoideae: Barlerieae: Barleriinae) with a predominantly palaeotropical distribution centred on eastern and southern Africa, the Indian subcontinent and Madagascar; only one species extends to the neotropics. A revised infrageneric classification of the genus is presented based on a combination of molecular phylogenetic studies using ddRADseq and plastid data, and analysis of taxonomically informative morphological traits. Two subgenera are upheld, subg. Barleria and subg. Prionitis . Within subg. Barleria , nine sections are recognised, supported by a multi-correspondence analysis of morphological traits across all species within the subgenus. In subg. Prionitis , three sections are maintained, two of which are further subdivided into six subsections. A diagnostic key to the subgenera, sections and subsections is presented to aid with identification. Whilst homoplasy is frequent across many morphological traits within Barleria , most species are readily placed within the classification by their combinations of traits. Lectotypes are provided for the generic synonyms Barleriacanthus Oerst., Barleriopsis Oerst., Barlerites Oerst. and Pseudobarleria Oerst. A revised checklist of Barleria recognises 307 species (346 taxa including subspecies and varieties) globally. All are placed at least to subgenus with the exception of the enigmatic B. conspicua Nees from Malaysia. Three species of subg. Barleria are not placed to section, whilst the remainder of the species are placed within a section or, where appropriate, a subsection, based on either combined molecular and morphological data or on morphological data alone. Species richness within the infrageneric taxa varies from one to 57 species, hence no one infrageneric taxon contains more than 20% of the total species richness in Barleria . 236 species (77%) of Barleria have an available extinction risk assessment, of which 42% are considered to be threatened globally, highlighting urgent conservation needs within the genus. This revised classification serves as the framework for future monographic work in Barleria .