Two new species of Barleria (Acanthaceae) from the Soutpansberg of Limpopo Province, South Africa

Two new species of Barleria subg. Barleria (Acanthaceae) are described from the Soutpansberg Centre of Plant Endemism in Limpopo Province of South Africa: Barleria soutpansbergensis and B. spinosissima. The habitat requirements, conservation status and taxonomic affinities of each species are discussed. Barleria soutpansbergensis is considered to be closely allied to the widespread and frequently cultivated southern African species B. obtusa, whilst B. spinosissima is morphologically most similar to B. bremekampii which has a restricted distribution in northern South Africa and Zimbabwe. Remarkably, the two new species are postulated to occasionally hybridise within the Soutpansberg. Both species are currently assessed as of Least Concern despite their restricted ranges. Barleria spinosissima is noted to be amongst the most densely spiny species of Barleria and, indeed, is a contender as one of the spiniest species of plant in South Africa.