Approaches to species delimitations in the genus Nostoc Vaucher 1803 ex Bornet et Flahault 1888

Life cycle as a stable trait in the evaluation of diversity of Nostoc from biofilms in rivers

“…Lazaroff & Vishniac (1961) observed this special stage and called it the 'aseriate stage'; they suggested that aseriate packets of cells differed from cells of hormogonia in structure as well as in the plane of division, and functioned as a spore-like reproductive stage, which could continue to grow slowly in an unfavorable environment (Lazaroff, 1973). However, Mollenhauer et al (1994) considered the term inadequate and agreed with previous suggestions (Geitler, 1932) that these cells divide in a single plane, but are pushed together by the confinement and external pressure of the envelopes, as it was evident in our results (Fig. 6a).…”

“…The genus Nostoc is a frequent member of many aquatic and terrestrial ecosystems, showing considerable morphological diversity (Mollenhauer et al, 1994;Dodds et al, 1995;Potts, 2000). Field populations of most Nostoc species are distinguished according to a characteristic set of macroscopic properties, unknown in other genera.…”

“…Field populations of most Nostoc species are distinguished according to a characteristic set of macroscopic properties, unknown in other genera. The life cycle of Nostoc is complex and considered an important feature for distinguishing of species (Geitler, 1932;Lazaroff & Vishniac, 1961;Komárek & Anagnostidis, 1989;Mollenhauer et al, 1994). In addition, there are numerous microscopic Nostoc spp., probably as many as the macroscopic species, which play different important roles in the biosphere (Mollenhauer et al, 1994(Mollenhauer et al, , 1999.…”

“…The life cycle of Nostoc is complex and considered an important feature for distinguishing of species (Geitler, 1932;Lazaroff & Vishniac, 1961;Komárek & Anagnostidis, 1989;Mollenhauer et al, 1994). In addition, there are numerous microscopic Nostoc spp., probably as many as the macroscopic species, which play different important roles in the biosphere (Mollenhauer et al, 1994(Mollenhauer et al, , 1999. However, the microscopic species in the genus are understudied, poorly known and likely represent many more species than currently described (Mollenhauer et al, 1994(Mollenhauer et al, , 1999Ř eháková et al, 2007).…”

“…In addition, there are numerous microscopic Nostoc spp., probably as many as the macroscopic species, which play different important roles in the biosphere (Mollenhauer et al, 1994(Mollenhauer et al, , 1999. However, the microscopic species in the genus are understudied, poorly known and likely represent many more species than currently described (Mollenhauer et al, 1994(Mollenhauer et al, , 1999Ř eháková et al, 2007). The information stemming from laboratory studies is often problematic, because many of the isolates were misidentified (Komárek & Anagnostidis, 1989;Wilmotte, 1994) or the information on the habitat and, especially, microenvironmental conditions was inadequately recorded.…”