Sea Ivory 
Shingled rock shield lichen 
Shrubby Cup Lichen 
Smooth Horn Lichen 
Smooth-footed Powderhorn 
Soft Strap Lichen 
Southern Soldiers Lichen 
Squamarina cartilaginea 
Squamarina gypsacea 
Star-tipped Reindeer Lichen 
Stereocaulon ramulosum 
Sterocaulon vesuvianum 
Thorn Cladonia 
Toy Soldiers 
Transcend cup lichen 
Trumpet Lichen 
Tube Lichen 
Tuckermannopsis americana 
Tuckermannopsis fendleri 
Turban Lichen 
Umbilicaria phaea 
Usnea cornuta 
Usnea hirta 
Usnea merrillii