Charophyta

The Charophyta are a division of green algae, including the closest relatives of the embryophyte plants. In some groups, such as conjugating green algae, flagellate cells do not occur. The latter group does engage in sexual reproduction, and motility does not involve flagella, since they are totally lacking. Flagellate cells in the form of sperm are found in stoneworts (Charales) and Coleochaetales.

Classification
Because they exclude the embryophytes, the Charophyta make a paraphyletic group (although the division Charophyta is occasionally restricted to simply the Charales or stoneworts, which are monophyletic). The Charophyta plus the embryophytes make up the Streptophyta, which is a monophyletic group.