Studies on type material from Kutzing's diatom collection VII: Achnanthes capensis Kutzing, Achnanthes capensis ss [var.] multiarticulata Kutzing and 'Achnanthes striata Suhr'

Kutzing described the species Achnanthes capensis Kutzing along with the variety Achnanthes capensis ss multiarticulata Kutzing. The latter was based on 'Achnanthes striata Suhr', a name first mentioned, without description or figure, in Drege's Zwei pflanzengeographische Documente. 'Achnanthes striata' became a synonym of Achnanthes capensis in Kutzing'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.