ABSTRACT
References 192
Color has long been used by light microscopists to distinguish the different algal phyla. The introduction of electron microscopy has shown that these differences in pigmentation are accompanied by differences in chloroplast ultrastructure, particularly in the appearance of the thylakoid system. Additionally, it has revealed not only variations in the fine structure of the plastid envelope, pyrenoids, and eyespots but also the presence of previously unknown substructures. Information about other distinguishing features such as chloroplast DNA has also been greatly enhanced by the use of several new techniques, including fluorescence microscopy and nucleotide sequencing.
