The Charophyceae are the green algae closest to plants.
Others classify Charophyceae as a class under division Charophyta, with Chlorophyta remaining a distinct division. There are also other possibilities.
Many of the complex plant traits related to sexual reproduction evolved first in charophyceans. Analysis of cpDNA (chloroplast DNA) shows that characteristics of plant chloroplasts also evolved first in the charophyceans, before the Zygnematales diverged from the lineage that lead to Coleochaetales, Charales, and the land plants.
Groups generally included within the Charophyceae are:
Charophyceae Facts for Kids. Kiddle Encyclopedia.