Umbilicaria Dillenii LichenUmbilicaria Dillenii, Tuckerm.
Habit and habitat.-On rocks.
Vegetative organs (thallus).-Leaf-like, leathery, the largest species known; brownish-green above, smooth and even; intensely black below with crowded, short fibrils, attached only at one point.
Fruiting organs (apothecia).-Orbicular, convex, attached only at the centre, the disk ridged concentrically.
Name.-Named in honour of the great botanist Dillenius.