Arthur Cronquist

A Consideration of the Evolutionary and Taxonomic Significance of Some Biochemical, Micromorphological, and Physiological Characters in the Thallophytes

A critical evaluation of the phylogeny and evolution of the plants classified as bacteria, algae, and fungi has been made. The evolution of chemical characters (porphyrins, carotenoids, carbohydrates, and lipids and sterols), micromorphological characters (cell wall, hereditary apparatus, flagellar apparatus, photosynthetic apparatus, mitochondria, and Golgi apparatus), and functional characters (metabolism of hygrogen, nitrogen, sulfur, and carbon, including respiration, photosynthetic energy transformation, and photosynthetic carbon fixation) are discussed. Phylogenetic interrelations among thallophytes are evaluated on the basis of each of these characters. The final section of the review discusses the phylogeny of organisms in the divisions and classes of the thallophytes as suggested by chemical, micromorphological, functional, and life cycle criteria.