Compare Ulnaria delicatissima
Ulnaria delicatissima var. angustissima has longer and more tapering valves with a higher stria density (Length: >200 µm, Stria density 13-14 in 10 µm; Patrick & Reimer, 1966). Ulnaria ulna has wider valves (6 to 8 µm, Lange-Bertalot & Ulrich, 2014) and is usually lacking a central area. Ulnaria acus, Fragilaria saxoplanktonica, and Fragilaria grunowii valves are more strongly tapering, with a higher striae density (11 to 13,12 to 15, and 23 to 28 in 10 µm, respectively; Lange-Bertalot & Ulrich, 2014).
LM scalebar = 10 µm
Length Range
158.2-262 µm
158.2-262 µm
Width Range
5 µm
5 µm
Striae in 10 µm
10-11
10-11
