Ulva rigida is a species of green algae belonging to the Ulvaceae family. The genus of this alga, Ulva, is edible and is known by its common name: Greenlaver. These have a wide geographic distribution along the coasts of the oceans. As mentioned previously, these algae are edible and are one of the most popular foods in Scandinavia, Great Britain, Japan, Ireland and China. These algae can be eaten raw in salads or soups, in this case already cooked. These are rich in proteins, fiber and vitamins and minerals, such as iron.

Ulva has sexual reproduction, having a haplodiplontic life cycle, and meiosis is pre-sporic (that is, meiosis occurs before the production of spores) and there is an alternation of generations. We conclude that this type of reproduction guarantees vast genetic variability, which is advantageous for the species.

Individuals of the genus Ulva appear to have a bright green color, occurring primarily in marine environments, even though there are species that live in brackish waters, which is a type of water in which there is more salt than fresh water and less than salt water. These algae are dependent on light, as they are photosynthetic individuals, and prefer habitats with rocky substrates so they can settle. This happens in calm, transparent waters 10 m deep (to capture light/radiation) and protected from the coast. Ulva species typically form dense clumps, which fill the most sheltered, full-sun areas in pools and coastal recesses.