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Pinnularia acrosphaeria is smaller, has broadly rounded apices, a narrower axial area and a less sinuous deflection of the proximal raphe ends.

Pinnularia bihastata has a more narrow axial area.

LM scalebar = 10 µm
Pinnularia cuneicephala LM4 Pinnularia cuneicephala LM6 Pinnularia cuneicephala LM1 Pinnularia cuneicephala LM8 Pinnularia cuneicephala LM5 Pinnularia cuneicephala LM7 Pinnularia cuneicephala LM2
Length Range
79-142 µm
Width Range
14-19 µm
Striae in 10 µm
6-7

Pinnularia acrosphaeria

W.Sm. 1853

Pinnularia acrosphaeria LM7 Pinnularia acrosphaeria LM6 Pinnularia acrosphaeria LM5 Pinnularia acrosphaeria LM4 Pinnularia acrosphaeria LM3 Pinnularia acrosphaeria LM2 Pinnularia acrosphaeria LM1
Length Range
52.7-82.9 µm
Width Range
9.7-12.0 µm
Striae in 10 µm
11-13

Pinnularia bihastata

(Mann) R.M.Patrick 1966

Pinularia bihastata LM6 Pinularia bihastata LM5 Pinularia bihastata LM7 Pinularia bihastata LM1 Pinularia bihastata LM4 Pinularia bihastata LM3 Pinularia bihastata LM2
Length Range
142-208 µm
Width Range
26-30 µm
Striae in 10 µm
5-6