Phylum: Charophyta Family: Desmidiaceae
Actinotaenium riethii J. Štastný & F.A.C. Kouwets 2012
Cells approximately cylindrical with a shallow and widely open sinus. Apices broadly rounded. Chloroplast stelloid, with 10 longitudinal ridges, all visible in apical view. Cell wall covered with fine pores. Named in honour of Professor Alfred Rieth.
Cell dimensions: L: 39–54 µm, B: 25–31 µm, L/B: 1.55–1.95.
Found in habitats subject to desiccation such as ephemeral pools and man-made structures like fonts and guttering. Often misidentified in the past so the distribution is unclear.
References:
Coesel, P.F.M. & Meesters, K.J. (2023 second edition) Desmids of the Lowlands.
Štastný, J. & Kouwets, F.A.C. (2012) New and remarkable desmids from Europe, taxonomical notes based on LM and SEM observations