Observations on the cytology and ultrastructure ofChrysamoeba radiansKlebs (Chrysophyceae)

Abstract

The amoeboid stage of Chrysamoeba radians Klebs is described by a combination of light and electron microscopy. Features of special interest include the presence of both a short flagellum and the vestigial stump of a second flagellum; a pyrenoid penetrated by channels of cytoplasmic matrix containing elements of the periplastidial network; the absence of a girdle lamella from the chloroplast; the relatively simple structure of the filiform rhizopodia; and the characteristic structural relation between the vestigial flagellum and the chloroplast, even though an eyespot and typical photoreceptor swelling are lacking. The formation of the temporary flagellate stage is described by light microscopy alone. The present account is compared with previous descriptions of Chrysamoeba radians and other species of Chrysamoeba and possible synonymy is indicated. Examination of the status of the genus Rhizochrysis suggests that this taxon should probably be considered to be a synonym of Chrysamoeba.