Article: The interrelationships of some Cretaceous Codiaceae (calcareous algae)

The anatomy and evolution of fossil codiacean calcareous algae referred to Arabicodium and Boueina (Jurassic-Cretaceous) and Halimeda (Upper Cretaceous-Recent) are discussed. It is considered that all are referable to one botanical genus Halimeda; differentiation of the earlier species-groups (Boueina and Arabicodium) was followed by hybridization and selection in the Upper Cretaceous, leading to Halimeda s.str., a group of species of more vigorous growth and showing a combination of characters from the older species-groups.