Glossary of lichen terms

This glossary provides an overview of terms used in the description of lichens, composite organisms arising from algae or cyanobacteria living symbiotically among filaments of multiple fungus species.

In 1825, Friedrich Wallroth published the first of his multi-volume work Naturgeschichte der Flechten ("Natural History of Lichens"), in which he proposed an alternative terminology based largely on roots from the Greek language.

His work, presented as an alternative to that of Acharius (of whom he was critical) was not well received, and the only terms he proposed to gain widespread acceptance were epi- and hypophloeodal, hetero- and homoiomerous, and gonidium, the last of which remained in use until the 1960s.

Gustav Wilhelm Körber, an early proponent of using spore structure as a character in lichen taxonomy, introduced amphithecium, muriform, and "polari-dyblastae", later anglicized to "polari-bilocular" and then shortened to polarilocular.

For example, after Gunnar Degelius objected to the use of gonidia for the algal partner, George Scott proposed the use of mycobiont and phycobiont for lichen components, recommendations that were generally accepted by lichenologists.