Common Frullania (Leafy Liverwort)

Common Frullania on birch bark. Forms dark designs on bark. Tiny leaves are closely overlapping and have sack-like lobes underneath. Dry leaves barely visable. Leafy stem 0.1 inches wide. Liverwort is closely related to moss and have a similar life cycle. Liverworts (8,500 species) may be leafy, like mosses, but the leaves are in two rows and flattened, although their may be a third row on the underside. Leafy forms occur on tree trunks or rocks, usually with mosses and lichens.