Question

Write a note on lichens.

Answer 1

Lichens are an example of symbiotic relationship between fungi and algae i.e. they co-exist for mutual benefit. The algal partner (usually blue-green algae or cyanobacteria) is known as phycobiont and it provides food for its fungal partner. The fungal partner is known as mycobiont and it absorbs water and minerals and supplies it to the phycobiont. Lichens can tolerate prolonged drought and drastic temperatures and therefore thrive in hostile habitats like rocks, barks of trees and the ground. Lichens are sensitive to air pollution. They are classified into three types - Crustose lichens (Rhizocarbon), Foliose lichens (Parmelia) and Fruticose lichens (Usnea).