Draba nemarosa (Whitlowwort)

This mustard appeared suddenly, in force, in 2003. I had never seen it before! Now it is everywhere, by the millions. I don't think anything can be done about it --- it's too numerous. Alas. We'll just have to see what it does. It can be pulled easily, but you could go nuts.

 

This photo shows how this plant can become robust, and develop mats that cover the soil, preventing anything else from growing.