Phylogenetic position of Ecballocystis and Ecballocystopsis (Chlorophyta).

Ecballocystis and Ecballocystopsis are two rare, green algal genera.Both have thalli that grow on rock surfaces in flowing water and attach to rocks by a thick mucilaginous pad.The algae have similar thalli structure, consisting of autospores in mother cell wall remnants.Ecballocystopsis differs from Ecballocystis in being filamentous instead of dendroid.In this study, new strains of Ecballocystis hubeiensis and Ecballocystopsis dichotomus were collected from China and cultured.Morphology was observed by light and electron microscopy.18S rDNA and rbcL sequences were determined and subjected to phylogenetic analysis.Both morphological and phylogenetic analysis indicated that Ecballocystis and Ecballocystopsis should be placed in the family of Oocystaceae.Ecballocystis was closely related to Elongatocystis in 18S rDNA phylogeny.The results of present study emphasize the high level of phenotypic plasticity of Oocystaceae.Within the family, cell arrangement can be solitary, colonial, dendroid, or filamentous.