柯林斯词典lichen /ˈlaɪkən/ (lichens) 1. N-MASS Lichen is a group of tiny plants that looks like moss and grows on the surface of things such as rocks, trees, and walls. 地衣 返回 lichen剑桥词典a grey , green , or yellow plant-like organism that grows on rocks , walls , and trees 地衣，苔蘚 返回 lichen