Phylum: Charophyta   Family: Desmidiaceae

Cosmarium subbioculatum F.A.C. Kouwets 2025

The cells depicted here have the general characteristics of C. bioculatum but are larger. A notable feature is the striking chloroplast with hydra-like extensions that reach the cell-wall. My images, where the chloroplast is visible, show a similar configuration. See Van Westen's C. bioculatum morpha (2024: 393).
Cell dimensions: L: 22-25.2 µm, B: 20-25 µm, Is: 7.8-9.5 µm; Th: c.11-12 µm, L/B: 0.95-1.15.
Found in slightly alkaline to mildly acidic habitats such as abandoned peat-cuttings and shallow moorland pools.

References: 
Kouwets, F.A.C. (2025). European Flora of the Desmid Genus Cosmarium.
Van Westen, M. (2024). Sieralgen in Drenthe.