Fragilaria vaucheriae and F. recapitellata have wider, shorter valves. Fragilaria vaucheriae, F. recapitellata, and F. capucina have wider, alternate striae. The central areas of large valves of F. vaucheriae and short valves of F. capucina can be entirely hyaline. Fragilaria vaucheriae and F. capucina have rostrate apices with only one rimoportula per valve. Ulnaria ulna has a central area that is bilateral and not expanded and may contain ghost striae.

LM scalebar = 10 µm
F Synegrotesca 6 125 46 F Synegrotesca 4 94 541 F Synegrotesca 3 76 5 F Synegrotesca 7 72 92 F Synegrotesca 2 63 82 F Synegrotesca 1 43 455
Length Range
43.5-133.9 µm
Width Range
2.6-3.9 at the central area, 2.0-3.0 at the poles µm
Striae in 10 µm

Fragilaria vaucheriae

(Kütz.) Petersen 1938

Fragilaria vaucheriae LM2 Fragilaria vaucheriae LM4 Fragilaria vaucheriae LM5 Fragilaria vaucheriae LM3 Fragilaria vaucheriae LM1
Length Range
6–30 µm
Width Range
4-5 µm
Striae in 10 µm

Also compare to

Fragilaria capucina


Fragilaria recapitellata

Lange-Bert. and Metzeltin

Ulnaria ulna

(Nitzsch) Compère