lichen
/ˈlaɪkən/noun
1
- a simple slow-growing plant which typically forms a low crust-like, leaf-like, or branching growth on rocks, walls, and trees地衣。
- Lichens are composite plants consisting of a fungus that contains photosynthetic algal cells. Their classification is based upon that of the fungal partner, which in most cases belongs to the subdivision Ascomycotina, and the algal partners are either green algae or cyanobacteria. Lichens obtain their water and nutrients from the atmosphere and can be sensitive indicators of atmospheric pollution.
2
- mass noun [usu. with modifier] a skin disease in which small round hard lesions occur close together苔藓病（一种皮肤病, 患者皮肤上出现密集的小圆形坚硬伤口）。
派生词
lichened
adjective （义项1）lichenology
noun （义项1）lichenous
adjective （义项2）词源
early 17th cent.: via Latin from Greek leikhēn.