About Usnea mutabilis Stirton
Usnea mutabilis Stirton, commonly called bloody beard lichen, is a fruticose (shrubby) lichen that grows 3–7 cm long. This species has a pale grayish-yellowish green color, and is darker green than other species in the Usnea genus. It branches unequally, and is typically anchored to tree bark via holdfasts. Most populations are found in eastern North America, and it sometimes occurs on chaparral shrubs or pines in California. Its surface is covered with isidia that grow either isolated or in clusters, and it does not produce apothecia. Its thick axis and medulla are colored dull red.
