In the Mojave desert, there were once large lakes that filled the valleys. When the lakes drained and dried up, they left large deposits of salt. Many of these salt flats are almost completely devoid of life, as the salinity is so high that they are instantly lethal to plant seedlings that attempt to take hold.
In some areas, where there are seeps or where a canyon creek system drains onto the flats, they can support some halophytic plants like Salicornia, Atriplex or salt grasses.
Despite the desolation of the salt flats, they have a surreal beauty to them. The crystals that form on the surface of the ground can be especially pretty. Sometimes, you can find unusuall sculpturing of the salt, such as these glassy sphere like structures.