Morphotypes of Klebsormidium from alpine soil crusts: (a–c) K. flaccidum (ASIB V100), (d–f) K. cf. flaccidum (KUE1), (g–j) K. elegans (PIT3), (k–n) K. crenulatum (SAG 2415). (a, b, d, e, g, i, m) Filaments of young (2–3 weeks old), and (c, f, h, g–l, n) filaments of old (2–3 months old) cultures; scale bars: 10 μm.