A lichen is a fungus (think mushroom) that “cultivates” species specific algae (or sometimes cyanobacteria) within itself. The algae photosynthesize and provide the fungus nutrients. In turn, the fungus provides a “home” and protection to the algae.
There are about six species of reindeer lichen along the Pacific Coast. Coastal reindeer lichen (Cladina portentosa) is an upright, shrub lichen that can grow up to about six inches high. This reindeer lichen forms extensive carpets, mats or tufts in open sites at lower elevations near the ocean or in coastal forests. It can be found along the North American coasts and in Great Britain and Europe. Its habitat is sandy, humus, peat or mineral soils on rock outcrops, compacted dunes and coastal forests.
Coast reindeer lichen is pale yellowish green and intricately branched from large main stems. The smaller lateral branches are mostly divided in 3s (occasionally 4s) and the penultimate branches are sometimes divided in 2s. The algae are located in groups scattered on the surface of the podetia (stalk-like body supporting the fruiting bodies).
Some forms of C portentosa contain usnic acid. Usnic acid is produced by lichen and was thought to occur only in lichen. However, hops have been shown to contain usnic acid. The coast reindeer forms containing usnic acid, which is bitter, are more yellowish. There are a few C portentosa forms that do not contain usnic acid. Those are more greyish. Usnic acid formation is induced by UV-B and is thought to protect the lichen from ultraviolet rays.
Caribou and reindeer eat reindeer lichen. Extracts from this lichen are also used, particularly in Europe, as an antibiotic and as perfume base.
Taxonomists have combined the Cladina genus into Cladonia. However this “clumping” is not universally accepted. The USDA Plant Database continues to use Cladina, and I like that designation because the reindeer lichen outwardly look quite different from many of the “pixie cup”, “soldier” and “matchstick” members of Cladonia. Cladina means “small branches” and derives from Latin. The species, portentosa, is also from Latin and means “monstrous” or “hideous”. I think the soft carpets (when damp) of coast reindeer lichen are quite pretty and definitely not hideous. Sometimes this species is also seen in the literature as Cladina impexa.
Stony Creek Trail in the Six Rivers National Recreation Area (Del Norte County CA) is where these coast reindeer lichen grow.