August 19, 2020 Castilleja exserta ssp. exserta Purple Owl’s Clover Lush spring display at the Skyline Serpentine Prairie: goldfields (Lasthenia californica), purple owl’s clover (Castilleja exserta), and new leaves of soaproot (Chlorogalum pomeridianum). Photo by Lech Naumovich. Where to see itSkyline Serpentine Prairie Revisited