Penium polymorphum (Perty) Perty, 1852
Most likely ID: n.a.
Synonym: n.a.
Sampling location: Sima Moor (Austria)
Phylogenetic tree: Penium polymorphum
Diagnosis:
- cells cylindrical or ellipsoidial with rounded ends
- length 35–75 µm
- cell wall with longitudinal striae, pass into reticulate pattern at apices
- 1–4 girdle bands
- two stelloid chloroplasts with longitudinal ribs and one pyrenoid
I found Penium polymorphum in July 2017 and in June 2024 in the Sima Moor (Austria). This desmid alga is not present in my local sites.
The cells of Penium polymorphum are cylindric-oval with each one stelloid chloroplast per semi-cell. The cell wall shows a characteristic pattern. In the middle an almost parallel longitudinal striation is visible what pass into a reticulate pattern towards the apices (s. fig. 1 c).
Fig. 1 a-c: Penium polymorphum. L = 75 µm. Three focal planes of a specimen found in June 2024 in the Sima Moor. Note the longitudinal striation (LS) of the cell wall which pass into a reticulate pattern (RP) towards the apices. Obj. 100 X.
Fig. 2 a-c: Penium polymorphum. L = 60 µm. Three focal planes of a second specimen. Obj. 100 X.