Umbilicaria Muhlenbergii LichenUmbilicaria Muhlenbergii, (Ach.) Tuckerm.
Habit and habitat.-On rocks.
Vegetative organs (thallus).-Large, leathery to rigid, irregularly pitted; olive-brown above, darker below.
Fruiting organs (apothecia).-Oblong and appressed, passing into irregular, often star-like plaited clusters without a common margin.
Name.-The specific name was given in honour of a Henry H. Muhlenberg.