Diatoms of North AmericaDiatoms of North America
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Compare Fragilariforma acidobiontica

(Charles) D.M.Williams and Round 1988

Compare

Fragilariforma nitzschioides, F. virescens, and F. acidobiontica all have linear valves with protracted ends, but the latter differs by having a lower stria density and the lack of a distinct sternum. Similar in valve outline to S. exiguiformis, F. acidobiontica differs by its more narrow apices, lower stria density and greater length.

LM scalebar = 10 µm
Ansp Gc 54250 Fragilariforma Acidobiota T7 Ansp Gc 54250 Fragilariforma Acidobiota T1 Ansp Gc 54250 Fragilariforma Acidobiota T5 Ansp Gc 54250 Fragilariforma Acidobiota T3 Ansp Gc 54250 Fragilariforma Acidobiota T6 Ansp Gc 54250 Fragilariforma Acidobiota T4
Length Range
32-67 µm
Width Range
3-4 µm
Striae in 10 µm
12-14 in the center valve, 14-15 at the ends

Fragilariforma nitzschioides

(Grunow) Lange-Bert. 2011

Fragilariforma nitzschioides LM3 Fragilariforma nitzschioides LM4 Fragilariforma nitzschioides LM5 Fragilariforma nitzschioides LM6 Fragilariforma nitzschioides LM2 Fragilariforma nitzschioides LM1 Fragilariforma nitzschioides LM7
Length Range
19-54 µm
Width Range
3.5-5.5 µm
Striae in 10 µm
18-25

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

Stauroforma exiguiformis

(Lange-Bert.) Flower, Jones and Round 1996

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