Compare Ulnaria acus
Ulnaria ulna differs by wider (6.3-7.7 µm), needle shaped (parallel sides) valves. Ulnaria delicatissima valves have needle shaped valves with short, constricted apices. Fragilaria grunowii has more narrow valves (2-4 µm) and more attenuated, narrow apices. Both Fragilaria crotonensis and Fragilaria tenera are smaller in size. Fragilaria crotonensis often has an inflated central area, has a higher stria density, strongly narrowing apices and forms long, ribbon-like colonies. Fragilaria tenera forms stellate colonies.
LM scalebar = 10 µm
Length Range
61-252 µm
61-252 µm
Width Range
4.2-4.9 µm
4.2-4.9 µm
Striae in 10 µm
11-12
11-12
Length Range
158.2-262 µm
158.2-262 µm
Width Range
5 µm
5 µm
Striae in 10 µm
10-11
10-11
Length Range
60-72 µm
60-72 µm
Width Range
2-3 µm
2-3 µm
Striae in 10 µm
17-18
17-18
Length Range
50-75 µm
50-75 µm
Width Range
2.0-2.5 µm
2.0-2.5 µm
Striae in 10 µm
15-17
15-17
