Eunotia trinacria

Krasske 1929      Category: Eunotioid
BASIONYM: Eunotia trinacria Krasske 1929
SYNONYM(S): Eunotia paludosa var. trinacria (Krasske) Nörpel and Alles in Alles et al. 1991 

Eunotia tetraodon


Eunotia triodon

LM scalebar = 10 µm = 80 pixels.


Contributor: Paula Furey - March 2012
Length Range: 8-24 µm
Width Range: 1.7-2.6 µm
Striae in 10 µm: 17-23 in the center valve


Valves are elongate-triangular, becoming more linear in larger specimens. Ventral margins are straight to weakly concave. Dorsal margins are slightly convex, with a slight central undulation. Valve ends are weakly subcapitate, subrostrate and not set off, or only slightly set off, from the main part of the valve. Helitoglossae are located close to the apices. Striae are parallel. The areolae are unresolved in the LM. Frustules are rectangular in girdle view.

Original Description

Basionym: Eunotia trinacria
Author: Krasske 1929
Length Range: 4-10 µm
Width Range: 2-4 µm
Striae in 10 µm: 17-22

Original Description

Original Images

Cite This Page:
Furey, P. (2012). Eunotia trinacria. In Diatoms of the United States. Retrieved August 28, 2016, from

Species: Eunotia trinacria

Contributor: Paula Furey

Reviewer: Marina Potapova


Alles, E., Nörpel-Schempp, M. and Lange-Bertalot, H. (1991). Taxonomy and ecology of characteristic Eunotia species in headwaters with low electric conductivity. Nova Hedwigia. 53: 171-213.

Furey, P.C., Lowe, R.L. and Johansen, J.R. (2011). Eunotia Ehrenberg (Bacillariophyta) of the Great Smoky Mountains National Park, USA. Bibliotheca Diatomologica 56: 1-134.

Krammer, K. and Lange-Bertalot, H. (1991). Bacillariophyceae. 3. Teil: Centrales, Fragilariaceae, Eunotiaceae. In Ettl, H., Gerloff, J., Heynig, H. & Mollenhauer, D. (Eds.). Süsswasserflora von Mitteleuropa. 2(3): 1-576. Gustav Fisher Verlag, Stuttgart, Germany.

Krasske, G. (1929). Beiträge zur Kenntnis der Diatomeenflora Sachsens. Botanisches Archiv 27(3/4): 348-380.

Lange-Bertalot, H., Bak, M., Witkowski, A. and Tagliaventi, N. (2011). Eunotia and some related genera. Diatoms of the European Inland Waters and Comparable Habitats. 6: 747 pp.

Links & ID's

Index Nominum Algarum (INA)

Original INA

California Academy of Sciences (CAS)

Eunotia trinacria CAS

North American Diatom Ecological Database (NADED)

NADED ID: 33212

Autecology Discussion

Found in streams, wetwalls, waterfalls, and sink holes, often associated with bryophytes.