RT Journal Article ID 1f4f32fd75b289e8 A1 Kondratyeva, N. V. A1 Kislova, O. A. T1 Variability of life cycles of Nostoc Vauch. (Cyanophyta) and problems of systematics JF International Journal on Algae JO IJA YR 2002 FD 2002-06-01 VO 4 IS 2 SP 72 OP 85 AB The taxonomic significance of a number of characters (life cycle type, morphological peculiarities of individuals during certain stages of the life cycle, dimensions and shape of vegetative cells within individuals of a certain age, peculiarities of akinetes, etc.) is discussed on the basis of authors' investigations and analysis of the literature data concerning ontomorphogenetic variability of Nostocaceae Elenk. The studied Nostoc Vauch. strains have been divided into three main groups on the basis of the whole complex of their characters. One of the common features for the representatives of the family Nostocaceae is the formation of oblique or pseudo-longitudinal cell walls in young trichomes. It results in the appearance of zigzag or pseudobilined trichomes. Ibis character distinguishes Nostocaceae from the closely resembling Anabaena Bory species (Anabaenaceae Elenk.). PB Begell House LK https://www.dl.begellhouse.com/journals/7dd4467e7de5b7ef,1c3680804af8ba00,1f4f32fd75b289e8.html