Studies on type material from Kützing’s diatom collection VII: Achnanthes capensis Kützing, Achnanthes capensis ß [var.] multiarticulata Kützing and ‘Achnanthes striata Suhr’

Kützing described the species Achnanthes capensis Kützing along with the variety Achnanthes capensis ß multiarticulata Kützing. The latter was based on ‘Achnanthes striata Suhr’, a name first mentioned, without description or figure, in Drège’s Zwei pflanzengeographische Documente. ‘Achnanthes striata’ became a synonym of Achnanthes capensis in Kützing’s protologue without it ever being validly published. All original specimens of Achnanthes capensis, A. capensis ß multiarticulata and A. striata are from Table Bay, Cape Province, Cape of Good Hope, South Africa. This account describes specimens from original material for all three names in Achnanthes and clarifies their relationships. As no morphological differences among these three named taxa could be found based on light and scanning electron microscopy observations, we place the other two names into A. capensis, as this name has priority. In short, A. capensis ß multiarticulata and A. striata are synonyms of Achnanthes capensis.