Compare Gomphonema stoermeri
Gomphonema apuncto lacks a stigmoid.
Gomphonema freesei has coarse striae.
Gomphonema amerhombicum is more clavate and larger in size.
Gomphoneis rhombicum has a stria density of 9.5-12 in 10 µm, length of 35-53 µm and width of 4.5-7.5 µm. Note that G. rhombicum has not been verified in North America.
LM scalebar = 10 µm
Length Range
19-45 µm
19-45 µm
Width Range
4-6 µm
4-6 µm
Striae in 10 µm
13-15
13-15
Length Range
21.0-30.7 µm
21.0-30.7 µm
Width Range
3.0-4.1 µm
3.0-4.1 µm
Striae in 10 µm
13-16
13-16
Length Range
35.0-53.9 µm
35.0-53.9 µm
Width Range
6.5-7.5 µm
6.5-7.5 µm
Striae in 10 µm
12.1-14.5 at valve center, 14.2-16.2 at headpole, 11.7-15.4 at footpole
12.1-14.5 at valve center, 14.2-16.2 at headpole, 11.7-15.4 at footpole
Length Range
22.5-60 µm
22.5-60 µm
Width Range
5.6-7.7 µm
5.6-7.7 µm
Striae in 10 µm
13-15 at mid-valve, up to 17 at headpole
13-15 at mid-valve, up to 17 at headpole
