Achnanthes indicatrix Lange-Bert. & Steindorf Achnanthes indicatrix Lange-Bert. & Steindorfis basionym for Achnanthidium indicatrix (Lange-Bert. & Steindorf) Lange-Bert. in Iconogr. Diatomol. 6: 272. 199911. (Basionym:) fig. 18: 10-14