views updated

Umbilicaria (order Lecanorales) A genus of lichens in which the foliose thallus is roughly circular in outline, either entire or lobed, and is attached to the substrate at a point in the centre of its lower surface. The apothecia are lecideine and black. Species are found mainly on non-calcareous rocks, chiefly in hilly and mountainous districts. See also IWATAKE.