Phylum: Charophyta Family: Desmidiaceaea
Cosmarium tyrolicum (Nordstedt) Krieger & Gerloff
Regarded as a northern and alpine species, its status in the Outer Hebrides is uncertain. Originally a variety of C. cymatopleurum, Krieger & Gerloff (1962) raised it to the rank of species, a view not shared by Kouwets (1999). West & West's (1908) concept has rather large dimensions, especially in width.
John, D.M. & Williamson, D.B. (2009) A Practical Guide to the Desmids of the West of Ireland
West, W. & West, G.S. (1908) A Monograph of the British Desmidiaceae, Volume 3
Kouwets, F.A.C. (1999) A check-list of desmids (Chlorophyta, Zygnemaphyceae) of France