Green Algae

Scientific Name (four classes): Charophyceae; Ulvophyceae; Chlorophyceae; Prasinophyceae

Status: Extant (alive today)

Oldest fossil anywhere: Proterozoic of Australia (about 1.8 billion years old)

Oklahoma fossil record: Only two classes, Chlorophyceae and Ulvophyceae, are reported. Fossils of Chlorophyceae are very, very small and easily overlooked from Cretaceous rocks. Fossils of Ulvophyceae are larger and frequently found in Ordovician through Devonian rocks. Receptaculids that are sometimes classified with ulvophyte green algae, but their relationships are not well known. Receptaculids are found in Ordovician through Devonian rocks in Oklahoma.