On the cell morphology and biology of Characiochloris apiculata (Chlamydophyceae)

Characiochloris apiculata KORSHIKOV, an epiphytic green alga described from northern Russia, was recognised in the Drevnice river, a left tributary of the Morava river (South Moravia, Czech Republic) following strong summer f loods. The species grew well for several months in laboratory subcultures o f the host alga, Oedogonium sp. Its cell cycle starts with a very short mon adoid stage (several tens of seconds) with a rather poorly developed chloro plast, a minute, hardly perceivable stigma and a few contractile vacuoles, which soon stop functioning in the substrate-attached cells. Neither in the monadoid stage nor in the early phases of the sessile stage the presence o f a cell wall could be confirmed. Observations of the life cycle seem to su pport the intermediate position of C. apiculata between Characiochloris and Characium, as proposed by FOTT (1972).