Comparative Ultrastructure of the Zoospores of Eight species of Characium (Chlorophyta)

Ultrastructure of the flagellar apparatus of the gametes ofGongrosira papuasica(Chlorophyta)

“…Swarmers described as zoospores varying in shape from elongate to ovoid have been reported previously for the genus (Tupa, 1974) and the gametes used in this study superficially resemble those swarmers. This study has shown that G. papuasica produces gametes whose ultrastructure resembles chlorophycean motile cells of Group I in the Neochloris and Characium complexes described by Watanabe & Floyd (1989a) and Floyd & Watanabe (1990). Group I is characterized as having motile cells with clockwise absolute orientation, thin walls, uninucleate vegetative cells, and pyrenoids penetrated by thylakoids.…”

“…Two recent ultrastructural studies on members of the Chlorophyceae sensu Mattox & Stewart (1984), include those of Watanabe & Floyd (1989a), and Floyd & Watanabe (1990) in which three subgroups of the Chlorophyceae were distinguished primarily on the basis of differences in flagellar apparatus structure in the genera Neochloris Starr and Characium A. Braun. Species of both genera have been shown to separate into the same groupings on the basis of DNA sequence data (Lewis, Since Gongrosira lacks pits (Stewart, Mattox & Floyd, 1973;Chappell, Stewart & Mattox, 1978) and other reproductive characters of the Trentepohliales, it appears to be artifically aligned with this order.…”

Phylogenetic position of the Sphaeropleaceae (Chlorophyta)

“…The genus Ankyra currently comprises six species and was assigned to the Characiaceae (NaÈ geli) Wille in Warming 1884 within the Chlorococcales, Chlorophyceae (Koma rek and Fott 1983). According to Wilcox et al (1992) and Floyd et al (1993) who studied the 18S rDNA phylogeny of Characium species, the Characiaceae are a polyphyletic assemblage and, therefore, the position of Ankyra in the phylogenetic system of green algae is unknown.…”

PSEUDONEOCHLORIS MARINA(CHLOROPHYTA), A NEW COCCOID ULVOPHYCEAN ALGA, AND ITS PHYLOGENETIC POSITION INFERRED FROM MORPHOLOGICAL AND MOLECULAR DATA

“…Molecular data were in agreement with the ultrastructural data, demonstrating a problem associated with using vegetative cell morphology alone for classification of members of this genus. In addition to Neochloris , four other genera of coccoid green algae have been shown to be polyphyletic using combined ultrastructural and molecular data ( Characium , Lewis et al 1992, Floyd et al 1993, Trebouxia , Friedl and Zeltner 1994, Pleurastrum , Friedl 1996, Chlorococcum , Nakayama et al 1996.…”