crustose lichen

例句：

1. 1. Lichens are fascinating organisms that can survive in extreme environments.
   地衣是令人着迷的生物，能在极端环境中生存。
2. 2. The crustose lichen on the rock wall was a reminder of nature's beauty.
   岩石墙上的地衣提醒我们大自然的美丽。
3. 3.Lichens play an important role in carbon cycling and are often used as indicators of environmental health.
   地衣在碳循环中起着重要作用，常被用作环境健康的指标。