The major taxonomic groups include red algae (Rhodophyta), green algae (Chlorophyta), and brown plus golden-brown algae (Chromophyta).
The Chromophyta are traditionally defined by 10 major classes which can be differentiated on the basis of ultrastructure and plastid characteristics (Green et al., 1989).
huxleyi) and dinoflagellates (as represented by Prorocentrum micans) to be independent eukaryotic lines of evolution unrelated to each other or the Chromophyta. In contrast, chromophyte algae plus oomycetes are seen as a cohesive evolutionary assemblage as are the animals, fungi, plants, and ciliates.
The Eustigmatophyceae have been considered to be outside the Chromophyta by some authors because of the possession of a distinctive eyespot, the lack of a girdle lamella in chloroplasts and the absence of dictyosomes from zoospores (Hoek, 1978; Hibberd, 1979).