Affinities and Interrelationships of the Characeae

Abstract

Developmental features of the Characeae are reviewed with reference to speculation on affinities and interrelationships of this group. A phylogenetic scheme is offered in which the Nitelloideae are considered a line distinct from the Charoideae. Nitella, on the basis of the presence of sympodial branching in its laterals and the greater degree of sterilization of its oogonium, is considered more advanced than Chara. Within Chara, ecorticate forms are considered to be derived from corticate forms. It is probable that there is some affinity between the Chaetophorales and the Charophyta, but the distinctive features of charophytes warrant their retention in a separate phylum. In an extension of Goebel's interpretation of the antheridium, the antheridial mother cell is compared to a nodal initial.