Golden-bowl mariposa lily, Calochortus concolor
Images copyright by Mark A. Chappell
The sago lilies, star lilies, mariposa lilies, etc. in the genus Calochortus grow widely in the western US and are among my favorite wildflowers I believe this one is the golden-bowl mariposa lily, Calochortus concolor. To be honest I'm not completely sure of the species identification, but it was abundant in the dry hills of southern San Diego County in June 2006. It was a rather windy day so the photos were shot at high shutter speed; one exposure caught a small native bee foraging in the flower.
Two other California Calochortus species are shown here and here.