An integrative approach to alpha taxonomy in Erica L. (Ericaceae) with three new species from the Western Cape, South Africa.

Abstract

The megagenus Erica L. (Ericaceae) comprises 851 species across its global distribution, with an extraordinary focus of diversity in the Cape Floristic Region (CFR) of South Africa where almost 700 species are endemic. The genus is remarkable for both its morphological diversity and the large number of species and subspecific taxa occurring in small populations, often in specialised habitats, putting them at high risk of extinction. Despite significant taxonomic work over the past century, part of this diversity remains undescribed. The sheer size of the genus, its morphological, ecological and geographical variability, and the absence of a modern, consolidated revision make alpha taxonomy challenging. By combining traditional taxonomic methods, standard DNA sequencing methods building on openly available data matrices, and an openly available specialised taxonomic tool for the genus, we present an integrative, reproducible approach to alpha taxonomy in Erica. This approach provided support for the recognition of three new species from the Western Cape in South Africa and aided in ruling out two further putative new species, confirming one as a natural hybrid and the other as a morphological variation within an existing species. We describe the three new species Ericaarida R.D.Hoekstra, Ericahessequae R.D.Hoekstra and Ericainopina J.H.J.Vlok.