Short Moss

A patch of short moss photographed in the Great Basin.

Biological soil crusts are an intimate association of soil particles, cyanobacteria, algae, lichens, bryophytes, and microfungi which live within or directly on top of the uppermost millimeters of soil. (Belnap, 2003)

Reference: 

Belnap, J. , Büdel, B. & Lange, O. L. (2003). Biological soil crusts: characteristics and distribution. In Biological Soil Crusts: Structure, Function, and Management (Volume 150, eds Belnap J. and Lange O. L.), pp. 3–30. Springer, Berlin and Heidelberg