Photo: Diane Edwardson, April 3, 2012. We still have no ID on these tiny and likely native wildflowers found above the historic viaduct footings. (Click on photo to enlarge.)
Photo: Diane Edwardson, April 3, 2012. The flowers are really small; my dog is a Shepherd mix. Arrow is pointing to the same flower from above photo.
*UPDATE April 15, 2012: For years, we'd hoped this was a native wildflower. It's not. It appears to be a Windmill Pink, also know as Common Catchfly (Silene gallica).
A longtime regular reader suggested it might be Silene noctiflora. Since the petals didn't look quite right to me, I looked up the genus, Silene, on Calflora. The native Silene species are far more interesting than the non-native variety. Thanks again to our readers for making suggestions.