altered andesite popcorn flower, Plagiobothrys glomeratus, Nevada, Virginia Range, Geiger Grade, Steamboat Creek - Truckee Meadows drainage, elevation 1630 m (5350 ft).

This humble annual Borage is one of a few rare plant species found on (and in this case limited to) these peculiar "altered andesite" soils in the foothills surrounding the greater Reno-Sparks area of far western Nevada. Deep hydrothermal alteration of these volcanic deposits left behind sulfide minerals, which slowly oxidize to sulfuric acid as they become exposed at the surface. This creates patches of highly acidic (pH 3-4), brownish orange to white soils that are largely barren of vegetation. Those few species that evolve to tolerate these harsh soil conditions enjoy reduced competition from other vegetation, but also become dependent on such conditions and often (like this species) don't survive anywhere else.