Cosmarium vogesiacum (Lemaire, 1883)

Most likely ID: n.a.


Synonym: n.a.


Sampling location: Simmelried


Phylogenetic tree: Cosmarium vogesiacum



  • semi-cell trapezoidal with flattened apex
  • length 19–23 µm, width 18–22 µm
  • sinus narrow, dilated to the margin
  • lateral margins of semi-cells with 5–7 granules
  • parallel to margin von semi-cells 2–3 rows of granules
  • in the center of the semi-cells 2 elliptical warts
  • parallel to sinus two rows of granaules
  • one pyrenoid per semi-cell
Cosmarium vogesiacum

So far I have only found Cosmarium vogesiacum in the Simmelried. However, I have only been able to find it there in the last 2 years. I cannot rule out the possibility that Cosmarium vogesiacum was already present before, but then only sporadically at most. In the meantime, the species has become very stubborn and I mainly find it in a shallow siltation zone. The specimens shown below are from July and September 2023.


Fig. 1 a-d: Cosmarium vogesiacum. L = 32 µm. Different focal planes of a slightly squashed specimen. Obj. 100 X.


Fig. 2 a-b: Cosmarium vogesiacum. L = 33 µm. A second, slightly squashed specimen. Obj. 100 X.