地衣,是真菌和藻类共同生活在一起的复合体。地衣中的藻类可进行光合作用,制造有机物;真菌从外界吸收水分和无机盐,为藻类提供光合作用的原料。并不是任何真菌都可以和任何藻类共生形成地衣体,每一种地衣中的真菌和藻类都是固定的。地衣约有26000余种。它们具有一定的形态,结构和生活习性,并能产生 Lichens are complexes where fungi and algae live together. The algae in the lichen can be used for photosynthesis to produce organic matter; the fungus absorbs water and inorganic salts from the outside and provides algae with photosynthesis raw materials. Not all fungi can coexist with any algae to form a lichen, and the fungus and algae in each lichen are fixed. There are about 26,000 kinds of lichens. They have a certain form, structure and habits, and can produce