( 423 ) 
Specimens examined: Mission Hills, San Diego, Abrams 3304. 
3. Opuntia BiceLovu Engelm. Pacif. R. Rep. 4: 50. 1856. 
Distribution: Southern Nevada and Arizona, southward to the 
western slopes of the Colorado Desert. Lower Sonoran. 
Specimens examined: Whitewater, Rose, 1908. 
4. OPUNTIA ACANTHOCARPA Engelm. & Bigel. Proc. 
Am. Acad. 3: 308. 1856. 
Type locality: “Mountains of Cactus Pass, between Santa Fe 
and the Western Colorado.” 
Distribution: Southern Utah and Nevada, southward through 
Arizona. Reported from Death Valley by Schumann. Lower 
Sonoran. 
Specimens examined: near Campo, Sykes; Mammoth Tank, 
Sykes. 
5. OPUNTIA EcHINOCARPA Engelm. & Bigel. Proc. Am. 
Acad. 3: 305. 1856. 
Type locality: “In the valley of the Lower Colorado.” 
Distribution: Western Arizona, westward through the Mohave 
and Colorado Deserts, and southward into Sonora and Lower Cali- 
fornia. Lower Sonoran. 
Specimens examined: Palm Springs, Dudley, Dec. 1902; Rock 
Creek, desert slope of the San Gabriel Mountains, Abrams & Mc- 
Gregor 564; Banning, Toumey, 1895; Barstow, Shaller. 
6. OpuNTIA CALIFORNICA (Nutt.) Coville, Proc. Biol. Soc. Wash. 
13: 119. 1899. 
Opuntia serpentina Engelm. Am. Journ. Sci. I]. 14: 338. 1852. 
Cereus californica Nutt. in Torr. & Gray, Fl. N. Am. 1: 555. 
1840. 
Type locality: ‘Arid hills and denuded tracts near St. Diego, 
California, common.” 
Distribution: Dry mesas and foothills of southwestern San 
Diego County, southward into Lower California. Lower Sonoran. 
Specimens examined: Tia Juana, Abrams 3474. 
