Cladonia 

Lichen is just about everywhere from urban areas to the desert, tundra and deep in the forest. Cladonia is a wonderful little lichen that has a slivery-green foliage and when it produces spores, it produces bright little red apothecia at the tips of long "branching" structures. I found these Cladonia on tree bark in a forest and on decomposing wooden fences. This is one of the easiest lichens to recognize.
Lichen is described in three different growth forms, crustose, squamulose, and fruticose. Cladonia falls under the category of fruticose lichen. These..."consist of simple or divided ranges that are round to flattened in cross section but with little difference between the upper and lower surfaces. Rhizines are lacking and cilia extremely rare. These lichens are bushy hart, or strap-shaped, attached at the base to trees or rocks and [in some times on soil]" (Hale p. 6). Squamulose lichen are lobed or leafy specimens and crustose lichen grow on the surfaces of things like on a headstone or bark. To really learn to ID lichen to species you have to learn to do tests using some chemicals such as calcium hypochlorite, potassium hydroxide or paraphenylenediamine. It is through these tests where you will get color reactions from the chemicals to help ID them.
Next time you take a walk, look just a little closer to your surroundings. You will find lichen everywhere. 
Resources:
http://www.sharnoffphotos.com/lichensB/cladonia_macilenta.html
https://lichens.twinferntech.net/pnw/species/Cladonia_macilenta.shtml
Hale, Mason E. How to Know the Lichens. Second Edition. (1979)
Hale, Mason E, Jr., Mariette Cole. Lichens of California. (1988)
Pojar, Jim & Andy MacKinnon. Plants of the Pacific Northwest Coast: Washington, Oregon, British Columbia 7 Alaska. (1994)
Purvis, William. Lichens. (2000)