[Wikipedia] Range, Identification: It is native to the western United States, from southwest Oregon down to northern California where it grows in the Klamath Mountains, Northern Coast Ranges, Cascade Range, and Sierra Nevada. Most of the known Californian locations are in the northern half of the state, as far south as Solano and El Dorado Counties, but there are isolated populations in Tulare and Mariposa Counties.[4] The species has also been reported from Douglas and Washoe Counties in Nevada.[5][6] It grows in dry, open woodlands and chaparral at 300 to 2,200 metres (980 to 7,220 ft), and it blooms in spring from February to July.[2] Hybrids among the 10 species of Fritillaria make identification challenging.[3] (link added by Mary Ann Machi)