Teloschistes crysophthalmus, a bright-orange, shrub-like epiphyte, is seen here growing on Fouquieria diguetii along the coast of Baja, Calif. Lichens are actually made up of two plants, an algae and a fungus, living in a symbiotic relationship. In desert environments, lichen will dry out completely and remain dormant until rain or dewfall provides enough moisture to make them active again. This ability allows lichens to survive some of the harshest environments on the planet. Because lichens are very sensitive to air pollution, scientists rely on them as a bioindicator species, like a natural environmental early warning system.
Image credit: ©Frank Bungartz, Ph.D., Arizona State University Lichen Herbarium