Compare Pinnularia undula var. major
Pinnularia undula var. major is most similar to Pinnularia decrescens and Pinnularia undula, but is larger. Pinnularia undula has parallel sides and only the larger valves are slightly triundulate, while Pinnularia undula var. major has strongly triundulate outline. Unlike Pinnularia decrescens, both Pinnularia undula and Pinnularia undula var. major have pronounced markings on the central area. Pinnularia divergens is similar in valve size and outline but its central area is rhombic and widens to a small fascia, reaching the valve margin.
LM scalebar = 10 µm
Length Range
96-156 µm
96-156 µm
Width Range
21-24 µm
21-24 µm
Striae in 10 µm
8-11
8-11
Length Range
63-87 µm
63-87 µm
Width Range
15-17 µm
15-17 µm
Striae in 10 µm
9-10
9-10
Length Range
80-93 µm
80-93 µm
Width Range
14-17 µm
14-17 µm
Striae in 10 µm
9-11
9-11
Also compare to
Pinnularia divergens
BioData Reference
Krammer 2000 Pl 28 Fig 1-6 Pl 29 Fig 1-6