Lichen aren't exactly a plant and aren't exactly a fungus. They are a combination of a fungus which gives the organism its basic structure, among other things, and there's an autotroph, usually a green algae or cyanobacterium. Of the twenty-thousand or so species, only 2 are not edible, though many are less palatable and/or require more preparation than others.
|Plants for a Future|
|Eat the Weeds: Episode 20|
- ↑ http://www.eattheweeds.com/www.EatTheWeeds.Com/EatTheWeeds.com/Entries/1939/7/28_Reindeer_Moss,_Cladonia_Evanii_Lichen.html