Ultrastructure and taxonomic position of the rare volvocalean alga, Chlorcorona bohemica

C. bohemica (Fott) Fott was previously of uncertain taxonomic affinities. The cell to cell connections, which are one of the chief features of the colony, are composed of wall extensions from adjacent cells. The outgrowths are connected by a fine fibrous component extending from wall to wall. The structure of the wall itself and the cell to cell connections, are similar to those of Pyrobotrys , although the connections in the latter are not as elongated. In addition, the flagellar apparatus of Chlorocorona is very similar to the flagellar apparatus of Pyrobotrys , and unlike that in other Chlorophyceae examined. These features suggest that Chlorcorona is closely related to Pyrobotrys and should be referred to the family Spondylomoraceae.