Question

what is the speciality of lichens?

Answer 1

The symbiotic relationship between fungi and Algae forms lichens.

Answer 2

A lichen, or lichenized fungus, is actually two organisms functioning as a single, stable unit. Lichens comprise a fungus living in a symbiotic relationship with an alga or cyanobacterium (or both in some instances). There are about 17,000 species of lichen worldwide.