Lace Lichen

Lace lichen has been used by Native Americans for medicinal purposes; it has antibacterial properties derived from ulnic acid. Lichens are an indicator of clean air, and lace lichen doesn’t thrive where there are significant levels of pollution. It has been impacted by wildfires caused by drought; researchers have found it failing to return to burn sites even ten years after a fire.

https://lpfw.org/our-region/wildlife/lace-lichen/
https://climatechange.ucdavis.edu/news/lichen-is-losing-to-wildfire-years-after-flames-are-gone/