This lifeform is found north of the Mason Dixon line in North America.

Powdered rosette lichen (Physcia caesia) is found throughout most of Canada and south through Washington, Oregon and northern California. This species is also found in the Rocky Mountains south to New Mexico. It is also found in New England.

Lecanorales class contains most of the Lichens that are found in North America. Included in this class are numerous families containing one or more genera.

Lichens (Phylum Lichenes) are an unusual type of life form in that Lichens are actually composed of two different kinds of life. Lichens are composed of algae and fungal threads working together to create an unusual group of life forms. Because of this combination of life forms, Lichens can be placed in a variety of places in the taxonomy tree. Any choice of taxonomic placement is open to dispute. Lichens can survive in a variety of harsh habitats. In fact, they are relatively more common in rather cold habitats. Lichens (Class Lichenes) are composite organisms that thrive under extreme climatic conditions, and, therefore, have an ability to grow where few other plants can survive, i.e., rocks, deserts, and extreme northern areas. They consist of a unique intergrowth of a fungus with a single- celled green algae. They are often brightly colored, as is the genus Claydonia (pictured). Many of them are intolerant of pollutants in the atmosphere. Their presence or absence indicates the degree of purity in the air. The Scots use lichens as the dye base for their Harris tweeds. Some are used as smoking products, some as medicines. Reindeer and Caribou depend to a large extent on these plants for food. A few species are poisonous.

Because lichens appear to be a combination of both an algae and a fungal type of growth, some taxonomists place them higher in the evolutionary scale than the fungi.

Most fungi are parasites on plants. Identification of many fungi is very difficult because their form and color is dependent on local conditions. One should not eat wild collected mushrooms as many edible species have poisonous look-alikes. Although we believe many of the species we show in this group are correctly identified,  we are also aware of instances where we doubt the identification.   We include these species to show the diversity of life,  as opposed to a method of precise species identification.