foliose lichen, picture by Karen Wise of Kingston, MississippiFoliose lichens such as the one shown on a tree trunk at the right take their name from the fact that they are vaguely similar to "foliage," or leaves. The  lichen in the picture is about six inches (15 cm) across.

reproductive "cups" of foliose lichenWhen foliose lichens such as the one at the left mature, reproductive "cups" form in the center. These cups, called apothecia (singular apothecium), are provided by the fungal part of the lichen, so it's no accident that they look like the fruiting structure of a sac, or cup,  fungus.

foliose lichenAt the right is another foliose lichen, this one on a tree twig. The whole picture covers an area about three inches across (8 cm). In this species, the fruiting bodies, instead of being tiny cups, appear at the curled edges of the lichen body.