Lichens have strong adaptability, especially cold tolerance and drought tolerance, and are widely distributed all over the world, from the north and south poles to the equator, from mountains and forests to deserts, from wet soil to dry rocks and bark. Lichens can be divided into epiphytes, lithophytes and aboveground soil because of different growth substrates.

(1) epiphytic lichen

This type is mostly epiphytic to trees in forests and shrubs, and the distribution of lichens on trees often has its fixed parts and is regularly distributed. Lichens are epiphytic on the crown, mainly dendritic lichens, such as usnea and snowflakes; In the upper part of the trunk, because the bark is smooth, most of them are epiphytic shellfish lichens, such as Lauraceae, Camelliaceae, gooseberry and so on. In the middle and base of the trunk, the bark is rough and bryophytes are attached to it to some extent. Therefore, most of these two parts of the trunk are epiphytic lichens, such as Yimei, centipede, cowhide leaves and Tumulus.

(2) Lithogenic lichens

On the exposed rocks, there are mainly shell-like lichens, such as Theaceae, Epidermis, Lepidoptera, Auricularia, Chlamydia, Orangeceae, Plumeria and so on. On rocks with bryophytes, there are mainly leaflike lichens, such as Meliaceae, Gelatinaceae, Selaginella, Litmus and so on.

(3) lichens on the ground

In this type, there are both shell lichens and leaflike lichens, such as litmus, pericarp and trichomes.