Eunotia hexaglyphis

Ehrenb. 1854      Category: Eunotioid

REPORTED AS: Eunotia tetraglyphis (Ehrenberg 1854) | Eunotia pentaglyphis (Ehrenberg 1854) | Eunotia polyglyphis (Grunow in Van Heurck 1881) 

Eunotia gibbosa


Eunotia horstii

LM scalebar = 10 µm = 80 pixels.


Contributor: Loren Bahls - July 2013
Length Range: 27-49 µm
Width Range: 8.6-12.3 µm
Striae in 10 µm: 13-17


Valves are weaked arched with a straight to slightly concave ventral margin and a moderately arched dorsal margin. The dorsal margin has 4 to 6 bluntly pointed undulations. The apices are rostrate to subcapitate and bluntly rounded. On the dorsal side, apices are set off from the valve by a shallow notch, resulting in “nose-like” ends. On the ventral side, apices are separated from the valve by a broad, shallow notch where the raphe is positioned on the valve face. Striae are radiate throughout and composed of very fine areolae, which number 34-40 in 10 µm.

Note that valve size is related to the number of dorsal undulations. The taxa E. tetraglyphis, E. pentaglyphis and E. polyglyphis were later names (homonyms) for different sizes of E. hexaglyphis.

Original Description

Author: Ehrenb. 1854
Length Range: µm
Striae in 10 µm:

Original Description

Original Images

Cite This Page:
Bahls, L. (2013). Eunotia hexaglyphis. In Diatoms of the United States. Retrieved April 19, 2018, from

Species: Eunotia hexaglyphis

Contributor: Loren Bahls

Reviewer: Paula Furey


Camburn, K.E. and Charles, D.F. (2000). Diatoms of Low-Alkalinity Lakes in the Northeastern United States. Academy of Natural Sciences of Philadelphia, Special Publication 18, 152 pp.

Ehrenberg, C.G. (1854). Mikrogeologie. Einundvierzig Tafeln mit über viertausend grossentheils colorirten Figuren, Gezeichnet vom Verfasser. Voss, Leipzig., Pl. 5, II, fig. 23 (iconotype).

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.

Patrick, R.M. and Reimer, C.W. (1966). The Diatoms of the United States exclusive of Alaska and Hawaii, V. 1. Monographs of the Academy of Natural Sciences of Philadelphia 13.

Links & ID's

Index Nominum Algarum (INA)

Original INA

California Academy of Sciences (CAS)

Eunotia hexaglyphis CAS

North American Diatom Ecological Database (NADED)

NADED ID: 33024

Autecology Discussion

Eunotia hexaglyphis occurs in somewhat acid to circumneutral waters of very low conductivity. The specimens shown here are from lakes and ponds in western Montana, northern Idaho and the Sierra Nevada Mountains of California. At these sites pH ranged from 5.5 to 7.1 and specific conductance ranged from 10 to 150 µS/cm.