Phylum: Charophyta   Family: Desmidiaceae

Cosmarium botrytis var. tumidium F. Wolle 1884

Described by Wolle (1884: 75) for its granulate tumour. However, his illustrations (L.c. pl. 17: 3-5) are misleading: in side view the tumour is close to the isthmus but in face view the sketchy outline of the tumour is central to the semicell. This may not be of significant taxonomic value as the semicell depicted below was found within a population of the nominate variety. The nominate variety has a shallow broad inflation at most.
Single cell dimensions: L: 60 µm; B: 53.7 µm; Is: 21.6 µm; L/B:1.12.
Found in mesotrophic ephemeral winter floodplains that dry out in the late spring.

References: 
Kouwets, F.A.C. (2025). European Flora of the Desmid Genus Cosmarium.