Original: Though the prokaryotic Cyanobacteria ( commonly referred to as blue-green algae ) were traditionally included as '' algae '' in older textbooks , many modern sources regard this as outdated as they are now considered to be closely related to bacteria .
Simplified: Though the prokaryotic Cyanobacteria ( formerly referred to as blue-green algae ) were included as '' Algae '' in older textbooks , this is outdated .