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Hygropetra balfouriana

(Grunow ex Cleve) Krammer and Lange-Bert. 2000      Category: Symmetrical biraphid
BASIONYM: Pinnularia balfouriana Grunow ex Cleve 1895

Hydrosera whampoensis


Karayevia amoena

LM scalebar = 10 µm = 80 pixels.


Contributor: Pat Kociolek - January 2011
Length Range: 5-19 µm
Width Range: 3-5 µm
Striae in 10 µm: 10-12


Valves are broadly linear to nearly elliptical in outline with rounded ends. The axial area narrow at the poles, widening to form a linear-elliptical to lanceolate central area. The raphe is straight, filiform, with distal ends not reaching the apices. The proximal raphe ends terminating quite a distance from one another. Striae are prominent, without visible punctuation in the LM, and radiate throughout.

Comments: Valve ultrastructure was used (Krammer 2000) to differentiate this genus from Pinnularia; this is the only species of the genus known in the US flora. This taxon is found in cool or mountainous regions across the US.

Original Description

Basionym: Pinnularia balfouriana
Author: Grunow ex Cleve 1895
Length Range: µm
Striae in 10 µm:

Original Description

Original Images

Cite This Page:
Kociolek, P. (2011). Hygropetra balfouriana. In Diatoms of the United States. Retrieved May 26, 2018, from

Species: Hygropetra balfouriana

Contributor: Pat Kociolek

Reviewer: Marina Potapova


Krammer, K. (2000). The genus Pinnularia. The Diatoms of Europe. Diatoms of Inland Waters and Comparable Habitats 1: 1-703.

Krammer, K. and Lange-Bertalot, H. (1986). Bacillariophyceae. 1. Teil: Naviculaceae. In: Ettl, H., J. Gerloff, H. Heynig and D. Mollenhauer (eds.) Süsswasserflora von Mitteleuropa, Band 2/1. Gustav Fisher Verlag, Jena. 876 pp.

Links & ID's

Index Nominum Algarum (INA)

Transfer INA

California Academy of Sciences (CAS)

Hygropetra balfouriana CAS

North American Diatom Ecological Database (NADED)

NADED ID: 221001

Autecology Discussion