Taxonomic revision of the southern African species of the genus Cynoglossum L. (Boraginaceae)

Abstract

The aim of the study is to provide a revision of the genus Cynoglossum in southern Africa. The genus is taxonomically problematic within the family Boraginaceae, due to the morphological similarities it shares with other closely related genera in the family. Cynoglossum plants are low-growing biennial, perennial, or rarely annual herbs which are recognizable by their hairy stems and leaves, the latter are usually basal and long petiolate. Based on the latest checklist, a total of eight species of this genus are listed for the study region: C. alticola, C. amabile, C. austroafricanum, C. geometricum, C. hispidum, C. lanceolatum, C. obtusicalyx (endemic to South Africa), and C. spelaeum. The occurrence of C. amabile in the region, however, requires further investigation since the only existing specimen was collected within a protected area in the KwaZulu-Natal province. Two specimens collected in the Doornpoort area in Pretoria, Gauteng province, assigned to this species appear to have been misidentified. Diagnostic characters are described, correct nomenclature, synonyms, typification, distribution maps, as well as the key for identifying the studied species, are provided.