Achnanthes inflata var. elata has more narrow ends than A. inflata. Achnanthes coarctata has a central constriction of the valve margin, compared to the central expansion of the margin of A. inflata. Achnanthes inflata has more capitate and broadly rounded apicies than other species in the genus.

LM scalebar = 10 µm
Achnanthes inflata LM7 Achnanthes inflata LM1 Achnanthes inflata LM2 Achnanthes inflata LM3 Achnanthes inflata LM4 Achnanthes inflata LM5 Achnanthes inflata LM6
Length Range
32-59 µm
Width Range
13.5–21.1 µm
Striae in 10 µm

Achnanthes longboardia

A.R.Sherwood and R.L.Lowe 2009

Achnanthes longboardia LM2 Achnanthes longboardia LM7 Achnanthes longboardia LM3 Achnanthes longboardia LM1 Achnanthes longboardia LM6 Achnanthes longboardia LM4 Achnanthes longboardia LM5
Length Range
22.6-47.8 µm
Width Range
8-10.5 µm
Striae in 10 µm
13-15 on raphe valve, 12-14 on rapheless valve

Achnanthes coarctata

(Bréb. ex W.Sm.) Grunow in Cleve and Grunow 1880

Achnanthes coarctata LM4 Achnanthes coarctata LM2 Achnanthes coarctata LM1 Achnanthes coarctata LM5 Achnanthes coarctata LM3
Length Range
32-70 µm
Width Range
9.4-15 µm
Striae in 10 µm
11 on the raphe valve, 9-10 on the rapheless valve

Also compare to

Achnanthes inflata var. elata