Genus CetrariaThe Genus CETRARIA, (Ach.) Fries
The Spanish-shield Lichens.-The members of this genus are generally found on trees, although sometimes they are found on rocks or even earth. The colour on the upper surface is bright yellow, greenish-yellow, straw, olive, or brown.
The thallus is expanded and leaf-like or shrubby (fruticulose or fruticose) with branches compressed or channelled; the lobes are flattened and broad: root-like growths on the under surface (rhizoids) are few or wanting.
Fine hairs (cilia) are frequently present and sometimes are numerous.
Soredia are rare.
The fruiting disks (apothecia) are medium in size or large; they are attached on or near the margin of the lobes; the disk itself is shield-shaped, light chestnut to dark reddish-brown. The shape of the disk suggested the name Cetraria, from cetra, a Spanish shield.
Iceland Moss Lichen
Pitted Cetraria Lichen