Phylum: Cyanobacteria   Family: Rivulariaceae

Calothrix stagnalis M.A. Gomont 1895

First described by Gomont (1895: 197). Trichomes up to 1 mm in length.
Cell dimensions: B: 8-12 µm (towards the base).
Found as an epiphyte on algae in shallow lochs and ponds. The distribution is unclear for the Outer Hebrides, but infrequently recorded.

References: 
Gomont, M.A. (1895). Note sur un Calothrix sporifère (Calothrix stagnalis sp. n.).
John, D.M., Whitton, B.A. & Brook, A.J. (2011 second edition). The Freshwater Algal Flora of the British Isles.