Chara inconnexa Allen (Streptophyta: Charales) and taxonomic ambiguities associated with subgymnophyllous species close to C. contraria A. Braun ex Kütz. s.str.

Chara inconnexa Allen has been found in the south of eastern Siberia. The specimens are described in detail. Chara inconnexa is a very rare species with a wide distribution range, but mostly inhabits the temperate and subtropical zones of the Northern Hemisphere. This freshwater species has been found in different types of water bodies. The possible causes of rare reports of C. inconnexa are presented. The taxonomical aspects are discussed. Whereas the holotype could not be critically identified for purposes of the precise application of the name to this taxon, its epitype should be retained. The taxonomic problems with subgymnophyllous species and forms close to C. contraria A. Braun ex Kütz. s.str. are outlined. The reassessment of the taxonomic value of branchlet characters and additional criteria application within a polyphasic approach are strongly required, as this will allow the recognition of subgymnophyllous species as a distinct species or forms of C. contraria or else will confirm the assumption that these are merely stages of ontogenesis or abnormal morphogenesis of C. contraria.