Phylum: Charophyta   Family: Desmidiaceae

Cosmarium holmiense var. integrum P. Lundell 1871

Semicells subtrapeziform with broadly rounded basal and apical angles and a well-marked constriction just below the apex, sides slightly convex with up to four undulations (not always visible), apex broadly rounded. Cell-wall smooth with small to medium pores. Chloroplast axile with usually ten longitudinal ridges, seen best in apical view, and one pyrenoid. Zygospore unknown.
Cell dimensions: L: 45-62 µm, B: 27-41 µm, Is: 14-22 µm; Th: 19-28 µm; L/B: 1.55-1.79.
This variety seems much more common than the nominate. Both are found in habitats that are subject to desiccation such as wet moss, ephemeral pools and shallow depressions.

References: 
Lundell, P.M. (1871) De Desmidiaceis, quae in Suecia inventae sunt, observationes criticae.
Kouwets, F.A.C. (in manuscript) European Flora of the Desmid Genus Cosmarium.