UPPER SURFACE: 4-15(-30) cm, smooth, dull, grayish to brownish
LOWER SURFACE: black, covered with dense black rhizines
CHEMISTRY: medulla C+ and KC+ red
Common in eastern North America, is it elsewhere in the world, too? I know there is a similar species in Japan, U. esculenta (sold as iwatake in markets, though apparently hard to find nowadays according to Japanese friends).
Common Name: Rock Tripe
Large grayish to brownish (greenish when wet) umbilicate lichen with black densely rhizinate lower surface. Will cover shaded rocks in deciduous forests in eastern North America, looking like someone has pasted withered old gray/blackened orange peels all over the rock.
On boulders and cliffs in deciduous forests, or near lakeshores.
Nothing comes close.
If boiled sufficiently, apparently this becomes edible. I found it very reminiscent of shoe leather, personally. But it’s listed in wilderness survival handbooks all the time as a good source of protein.
