Red Car Property: Probably Native

Photo: Diane Edwardson, April 19, 2011.  (Click on photo to enlarge.)

How do you know if this is probably a native wildflower?  There are very few and are very hard to find. 

They bloom in the same spot every year, never taking over an entire swath of land.  In this case, above the historic viaduct footings.  They also bloom on the same slope with the Tomcat Clover and other native species.