Mesostigmatophyceae

The Mesostigmatophyceae are a class of basal green algae found in freshwater originally containing two species in a single genus, Mesostigma. Now, a clade containing "Chlorokybus" and "Spirotaenia" has been added."". The Mesostigmatophyceae are either placed as sister to all other green algae, or more conventionally as sister to all Streptophyta.