Achnanthes metaffinis Lange-Bert. & Steindorf Achnanthes metaffinis Lange-Bert. & Steindorfis basionym for Achnanthidium metaffine (Lange-Bert. & Steindorf) Lange-Bert. in Iconogr. Diatomol. 6: 272. 199911. (Basionym:) fig. 1: 14-18