1) Branch of biology 
Lichenology is the branch of mycology that studies the lichens, symbiotic organisms made up of an intimate symbiotic association of a microscopic alga (or a cyanbacterium) with a filamentous fungus. Study of lichens draws knowledge from several disciplines: mycology, phycology, microbiology and botany and scholars of lichenology are known as liche...
study of lichens
• (n.) The science which treats of lichens.
Li`chen·ol'o·gy (-jȳ) noun [ Lichen + -logy .] The science which treats of lichens.