[Wikipedia] Range, Similarity to C. venustus: It is endemic to California, a common member of the flora in several types of habitat across much of the state. It is most abundant in the Coast Ranges and in the Foothills of the Sierra Nevada. This plant resembles Calochortus venustus, a chief discriminant being the oval to crescent shaped nectary of C. luteus compared to the squarish nectary of C. superbus. (link added by Mary Ann Machi)