What are lichens?

Lichens are plants but they do not have roots, leaves or flowers. There are around 16,000 species of lichens. They are found in almost all places. Lichen is actually two plants growing together. One is a fungus and the other is an algae. The greater part is a grey-coloured, thread-like fungus. Bright green cells of algae are held among the fungus fibres. The fungus cannot make its own food so it uses food made by the algae.