A taxonomic revision of Acanthaceae tribe Barlerieae in Angola and Namibia. Part 1

Abstract

In the first part of a taxonomic revision of the tribe Barlerieae (Acanthaceae) in Angola and Namibia, two of the four major clades of the genus Barleria L. are studied in detail, namely subg. Barleria and subg. Prionitis sect. Prionitis. Using standard morphology-based taxonomic methods, a total of 32 species and 39 taxa are delimited, of which 12 are endemic to Namibia, nine are endemic to Angola, a further four are restricted to the two countries combined and four are largely confined to the region. Hence, nearly 70% of the taxa are endemic or near-endemic to Angola and Namibia. Full descriptions, citations of types and representative specimens, and notes on their habitat(s), ecology and biogeography are provided for each taxon. Seven new species (Barleria calole, B. crabbeoides, B. craveniae, B. deserticola, B. fernandae, B. namba and B. rupicola), two new subspecies (B. lanceolata subsp. tristis and B. prionitoides subsp. strigulosa) and one new variety (B. rigida var. spinissima) are described. In addition, Barleria namutonensis Oberm. is treated as a subspecies of B. prionitoides, and B. dinteri Oberm. is treated as a subspecies of B. coriacea Oberm. and the necessary new combinations are made, whilst B. schenckii Schinz is resurrected as a good species. Eleven names in Barleria are lectotypified. A preliminary assessment of the conservation status and extinction risk is provided for each taxon. Of the 39 taxa enumerated, the majority are assessed to be of Least Concern, but one is assessed as Endangered, four as Vulnerable, one as Near Threatened and six are currently considered to be Data Deficient.

Phylogenetic relationships among species of Barleria (Acanthaceae, Lamiales): Molecular data reveal complex patterns of morphological evolution and support a revised classification

“…When a fifth, medial staminal element is present, it is almost always entirely sterile. It is hypothesized that the reduced lateral stamens bearing antherodes constitute a self‐fertilization mechanism (Darbyshire & al., ). In B.elegans S.Moore ex C.B.Clarke, for example, they transfer pollen to the stigma as the corolla abscises and the tube slides over the stigma (Singh & al., ).…”

“…Detailed morphological observations of a large number of Barleria species and preparation of identification keys for the Flora of Tropical East Africa (Darbyshire & al., ), Flora Zambesiaca (Darbyshire & al., ) and a forthcoming treatment for Angola and Namibia (Darbyshire & al., ) have raised questions about whether the current classification is reflective of evolutionary history and motivated the present study. Our overall goal is to advance our understanding of evolutionary relationships in Barleria by substantially increasing the number of species sampled for an estimate of phylogenetic relationships based on molecular data.…”

New scientific discoveries: Plants and fungi

“…The time from the first collection of a putative new species to its formal description varies greatly. Barleria deserticola (Figure 2a), from the Namib coastal desert was first collected 160 years ago, by the explorer Friedrich Welwitsch, but was only re‐found in 2009 by US botanist Erin Tripp and named in 2019 (Darbyshire, Tripp, & Chase, 2019). In contrast, the description and publication of Inversodicraea koukoutamba (Podostemaceae) collected from a waterfall in Guinea in 2018 took only one year from the first collection (Cheek, Molmou, Jennings, Magassouba, & van der Burgt, 2019).…”

Phytochemicals and Biological Activities of Barleria (Acanthaceae)

“…The name Barleria was provided by a French botanist and Dominican monk, Jacques Barrelier (1606–1673), who dedicated his spare time to botany [ 34 ]. Barleria is the third largest genus in the family Acanthaceae after Justicia and Ruellia [ 35 , 36 , 37 ], and it is the most species-rich genus in Barlerieae [ 38 ]. This genus includes approximately 300 species of shrubs and herbs that are distributed in the subtropical and tropical regions of the world [ 39 , 40 , 41 , 42 , 43 ].…”