Meridion circulare has markedly heteropolar valves.

Odontidium mesodon has more elliptic valves and a higher stria density.

The costae of Odontidium hyemale are oriented diagonally.

LM scalebar = 10 µm
Meridion lineare LM1 Meridion lineare LM2 Meridion lineare LM3 Meridion lineare LM4 Meridion lineare LM5 Meridion lineare LM6 Meridion lineare LM7
Length Range
11-31 µm
Width Range
4.8-8.0 µm
Striae in 10 µm
11-19, mostly 16-18

Odontidium mesodon

(Ehrenb.) Kütz. 1844

Odontidium mesodon LM7 Odontidium mesodon LM2 Odontidium mesodon LM6 Odontidium mesodon LM4 Odontidium mesodon LM3 Odontidium mesodon LM1 Odontidium mesodon LM5
Length Range
10–40 µm
Width Range
6–12 µm
Striae in 10 µm

Meridion circulare

(Grev.) C.Agardh 1831

Meridion circulare LM3 Meridion circulare LM2 Meridion circulare LM1 Meridion circulare LM6 Meridion circulare LM5
Length Range
17-80 µm
Width Range
3-4 µm

Odontidium hyemale

(Roth) Kütz. 1844

Odontidium hyemale LM4 Iwb 0002 2 20170509 05 Cl Odontidium hyemale LM1 Iwb 0002 2 20170509 03 Cl Iwb 0025 1 20170509 05 Cl Odontidium hyemale LM2 Odontidium hyemale LM3
Length Range
16.7-51.3 µm
Width Range
6.6-10.6 µm
Striae in 10 µm