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Gomphonema germainii

Kociolek and Stoermer 1990      Category: Asymmetrical biraphid

Gomphonema freesei


Gomphonema gibba

LM scalebar = 10 µm = 80 pixels.


Contributor: David R.L. Burge - December 2016
Length Range: 25-44 µm
Width Range: 4.6-6.3 µm
Striae in 10 µm: 10-12 at the valve center, 12-14 at the headpole, 14-15 at the footpole


Valves are linear-clavate to clavate. The apices are acutely rounded, markedly so in the footpole. The axial area is variable; linear-clavate valves have a narrowly lanceolate axial area, while clavate valves have a more broadly lanceolate axial area. Striae are weakly radiate at the valve center, becoming parallel toward the apices. The raphe is filiform and weakly undulate. The proximal raphe ends are deflected to the same side as the stigmoid. The distal raphe ends at the headpole is deflected to the opposite of the stigmoid.

Kociolek and Stoermer (1990) considered this taxon to be highly variable. The isotype slide (ANSP GC 55687a) showed two distinct morphologies of G. germanii. (see autecology section for additional images). One morphology is linear-clavate, with a narrow axial area. The second morphology is clavate, with a wide axial area. Comparisons to similar taxa were based on Lange-Bertalot (1986).

Original Description

Author: Kociolek and Stoermer 1990
Length Range: 20-58 µm
Width Range: 4.5-7.0 µm
Striae in 10 µm: 9-11

Original Description

Valves linear-clavate to lanceolate clavate with headpole apiculate and footpole narrow. The striae are punctate, radiate, 9-11|10 µm. The central area has the median stria approaching the isolated stigma. The axial area of variable width. Length 20-28 µm. Breadth 4.5-7.0 µm. The raphe is undulate and lateral and has prominent internal proximal raphe ends.

Original Images

Cite This Page:
Burge, D. (2016). Gomphonema germainii. In Diatoms of the United States. Retrieved May 25, 2018, from

Species: Gomphonema germainii

Contributor: David R.L. Burge

Reviewer: Marco Cantonati


Kociolek, J.P and Stoermer, E.F. (1990). A new, highly variable Gomphonema (Bacillariophyceae) species from the Laurentian Great Lakes. Ouvrage délié á H. Germain, Koeltz, 139-144.

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)

California Academy of Sciences (CAS)

Gomphonema germainii CAS

North American Diatom Ecological Database (NADED)

NADED ID: 37296

Autecology Discussion

Gomphonema germanii has been reported from epilithic habitats of Lake Huron, Lake Michigan, and Lake Superior (Kociolek and Stoermer 1990).


Gomphonema germanii morphological group 1

Credit/Source: Academy of Natural Sciences of Drexel University GC 55687a

Gomphonema germanii morphological group 2

Credit/Source: Academy of Natural Sciences of Drexel University GC 55687a