Appearance''U. mammulata'' is among the largest lichens in the world. The thallus of ''U. mammulata'' is usually 4 to 15 centimeters in diameter, but specimens have been known to reach 63-centimetre in the Smoky Mountains of Tennessee. The smooth upper surface is a reddish-brown to grayish-brown color and the lower surface is pitch black.
HabitatThis species is found on boulders and steep rock walls in forests and around lakes. It grows on several types of rock substrate, such as acid rock, sandstone, quartz, and granitic rock. Like most lichens, ''U. mammulata'' is sensitive to air and water quality. If conditions are optimal, seeing rocks or cliffs covered in dinner plate sized thalli is not unusual. However, it has been suggested that ''U. mammulata'' is not as sensitive to pH and water quality as it is to the frequency and duration of precipitation.
Some text fragments are auto parsed from Wikipedia.