Phylogenetic position of the Ulvophyceae and evolutionary relationships among its main lineages
The Ulvophyceae are currently regarded as one of the main classes of the Chlorophyta, but the relationship of the class with other classes of Chlorophyta is still a matter of debate. Also the relationship among ulvophyte lineages have been difficult to resolve, and in addition, monophyly of the class has been questioned. Current view of phylogenetic relationships and uncertainties are summarized in Fig. 5. The Chlorophyta are one of the two main clades of green plants (also known as Viridiplantae or Chloroplastida), the other clade being the Streptophyta, which includes several freshwater green algae and the land plants (Embryopsida). The Chlorophyta includes several early diverging, species-poor clades of mostly unicellular marine and freshwater green algae (Prasinophytes), and the morphologically and ecologically diverse core Chlorophyta.