Phylum: Charophyta Family: Closteriaceae
Closterium ralfsii var. hybridum Rabenhorst 1863
West & West (1904: p. 183, pl. 24: 8-13) describe the nominate as very rare but this variety as widespread in many parts of the world. They make no mention of any records for Scotland. An acidophile which is probably quite rare in Britain.
References:
Rabenhorst, L. (1863) Kryptogamen-Flora von Sachsen, Ober-Lausitz, Thüringen und Nord-Böhmen, mit Berücksichtigung der benachbarten Länder: erste Abtheilung: Algen im weitesten Sinne, Leber und Laubmoose.
West, W. & West, G.S. (1904) A Monograph of the British Desmidiaceae, Volume 1.
John, D.M. & Williamson, D.B. (2009) A Practical Guide to the Desmids of the West of Ireland.
Coesel, P.F.M. & Meesters, K.J. (2007) Mesotaeniaceae and Desmidiaceae of the European Lowlands.