Visit us at

Diatoms of the United States is now known as Diatoms of North America.
This site has been redesigned and updated, and will be closing soon.

Nitzschia incognita

Legler and Krasske 1940      Category: Nitzschioid

Nitzschia fonticoloides


Nitzschia inconspicua

LM scalebar = 10 µm = 80 pixels.


Contributor: Loren Bahls - July 2016
Length Range: 19-48 µm
Width Range: 2.2-3.0 µm
Striae in 10 µm: 29-31


Valves are linear-lanceolate with narrow, acutely rounded apices. Fibulae on the eccentric keel number 11-15 in 10 µm. On most valves the two median fibulae are more widely spaced, giving the appearance of a “central nodule”. Striae are parallel and composed of indistinct areolae.

This taxon is very similar to and may be conspecific with Nitzschia radicula Hustedt.

Original Description

Author: Legler and Krasske 1940
Length Range: 34-52 µm
Width Range: 2 µm
Striae in 10 µm: 30

Original Description

Original Images

Cite This Page:
Bahls, L. (2016). Nitzschia incognita. In Diatoms of the United States. Retrieved May 24, 2018, from

Species: Nitzschia incognita

Contributor: Loren Bahls

Reviewer: Marina Potapova


Krammer, K. and Lange-Bertalot, H. (1988). Bacillariophyceae. 2. Teil: Bacillariaceae, Epithemiaceae, Surirellaceae. In: Ettl, H., J. Gerloff, H. Heynig and D. Mollenhauer (eds.) Susswasserflora von Mitteleuropa, Band 2/2. Gustav Fisher Verlag, Jena.

Lange-Bertalot, H., Kulbs, K., Lauser, T., Norpel-Schempp, M. and Willmann, M. (1996). Diatom taxa introduced by Georg Krasske: Documentation and revision. Iconographia Diatomologica (H. Lange-Bertalot, ed.), Vol. 3, Koeltz Scientific Books, Konigstein, 358 pp.

Legler, F. and Krasske, G. (1940). Diatomeen aus dem Vansee (Armenien). Beiträge zur Ökologie der Brackwasserdiatomeen. I. Bot. Centralbl. Beih. 60: 335-345.

Links & ID's

Index Nominum Algarum (INA)

Original INA

California Academy of Sciences (CAS)

Nitzschia incognita CAS

North American Diatom Ecological Database (NADED)

NADED ID: 48340

Autecology Discussion

The specimens pictured on this web page are from streams on the Northwestern Great Plains of Montana and from the Weiser River in northern Idaho. Krammer & Lange-Bertalot (1988) report this species from electrolyte-rich to brackish waters. It was originally described from a lake in Turkey and also reported from the North Sea Coast of Belgium. Nitzschia radicula is very similar to N. incognita, both in morphology and autecology.