Zygnematophyceae

Zygnematophyceae (or Conjugatophyceae) is a class of green algae in the division Charophyta. It contains two orders: Zygnematales and Desmidiales. From all the Charophyta, the Zygnematophyceae are considered to represent the closest relatives to land plants.

Sexual reproduction in the Zygnematophyceae takes place through a process called conjugation. Here cells or filaments of opposite gender line up, and tubes form between corresponding cells. The male cells then become amoeboid and crawl across the female, or sometimes both cells crawl into the connecting tube. The cells then meet and fuse to form a zygote, which later undergoes meiosis to produce new cells or filaments. As in plants, only the female passes its chloroplasts on to the offspring.