What is common and what is the difference in sexual reproduction of Chlamydomonas and Spirogyra?

It is worth starting with the differences in sexual reproduction of Spirogyra and Chlamydomonas. In Chlamydomonas, zygotes are formed by merging germ cells into pairs. After the resting stage, the zygote forms zoospores after meiosis. An adult grows from zoospores. In Spirogyra, sexual reproduction is conjugation. When conjugated, a zygote is formed as a result of the process of fusion of two cells of different spirogyra. But the spirogyra experience the resting stage in the form of a zygospore. In the spring after meiosis, four spores are produced from the zygospore. Of the four, one grows into an algae, but the rest die. Common to such different sexual processes is that both spirogyra and chlamydomonas have all stages of haploid, and only the zygote stage (in spirogyra and the zygospore stage) is diploid.