macrolichen

例句：

1. 1. The macrolichen on the rock wall is a rare and beautiful sight.
   岩石墙上的外生菌丝层是一种罕见的美丽景象。
2. 2.The scientist found that the macrolichen was a natural defense against UV radiation.
   科学家发现，这种外生菌丝层是一种天然的抵御紫外线辐射的防御机制。
3. 3.Macrolichen is often used as an indicator of ecological health in mountainous regions.
   外生菌丝体常被用作山区生态健康的指标。