Rocella is a genus of lichen-forming fungi, primarily found in coastal regions. These organisms are known for their ability to produce natural dyes, particularly orchil, which is used to create purple and violet colors in textiles. Rocella thrives on various substrates, including rocks and tree bark, and plays a role in the ecosystem by contributing to soil formation. The most notable species within this genus is Rocella tinctoria, commonly referred to as the "orchil lichen." This species has been historically significant in the dye industry, especially before synthetic dyes became prevalent. Rocella is also important for biodiversity, providing habitat for various microorganisms.