See below Prasiola is a genus of macroscopic green algae, found in a variety of habitats ranging from terrestrial, freshwater, to marine.

[2]: 227 Plants belonging to the genus Prasiola were first described by John Lightfoot in 1777 in his series Flora Scotica, as the name Ulva crispa.

[1] Molecular phylogenetic studies have found that Prasiola is sister to a clade containing the similar genus Rosenvingiella and Rosenvingiellopsis.

[8] The studies have also shown that freshwater and marine species of Prasiola are representatives of a lineage that back-colonized their habitats from a terrestrial ancestor; this is the opposite situation of colonization from sea to land and with few documented examples.

Terrestrial species often inhabit soil, rocks, and tree trunks; they are particularly common in nitrogen-rich areas such as guano deposits.

[3] Marine Prasiola often have the ascomycete fungus Mastodia tessellata (also known as Kohlmeyera complicatula, Turgidosculum complicatulum) growing within their thalli.