Fig. 22. Staurosirella leptostauron SEM (6.5 micrometer bar). Fig. 23. SEM of large apical field pore visible on valve apex (2.5 micrometer bar). (Plate of SEM's courtesy of Diatom Research, Biopress, Ltd., Williams and Round 1987)
In Lake Michigan, the length of Fragilaria leptostauron ranges from 8-30 micrometers. The breadth ranges from 7-18 micrometers and the striae are 5-9 in 10 micrometers. In the Great Lakes samples, this species was highly variable in valve shape and deformed and abnormal specimens were commonly found (Stoermer and Yang 1969).