Parmelia meiophora

Parmelia meiophora is a species of corticolous (bark-dwelling) foliose lichen in the family Parmeliaceae. Described from collections made in Yunnan, China in 1889, this lichen is known from high-elevation cloud forests in southwestern China, where it grows on tree bark at elevations of roughly 3,000–4,000 metres; it has also been recorded from Nepal. The species forms loosely attached, greenish-grey rosette-shaped growths 8–15 cm across, characterized by a shiny surface covered with numerous tiny projections (isidia) and very small pale pores. It is distinguished by its strongly branched root-like structures on the black undersurface and its chemistry, which produces distinctive colour reactions when tested with potassium hydroxide solution: the cortex turns weakly yellow while the interior changes from yellow to red....read more on Wikipedia.