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Fragilariforma virescens valves are greater in length and width and have rostrate ends. In girdle view, striae extend across the valve mantle.

LM scalebar = 10 µm
Stauroforma exiguiformis LM4 Iwb 0040 06072015 08 Cl Stauroforma exiguiformis LM1 Stauroforma exiguiformis LM3 Stauroforma exiguiformis LM5 Stauroforma exiguiformis LM2
Length Range
4-22 µm
Width Range
3-4 µm
Striae in 10 µm
16-20

Fragilariforma virescens

(Ralfs) D.M.Williams and Round 1988

Fragilariforma virescens LM6 Fragilariforma virescens LM3 Fragilariforma virescens LM1 Fragilariforma virescens LM4 Fragilariforma virescens LM2 Fragilariforma virescens LM5
Length Range
15-60 µm
Width Range
6.5-7.0 µm
Striae in 10 µm
20-22

Also compare to

Stauroforma inermis

Flower et al.