64 BULLETIN 56, UNITED STATES NATIONAL MUSEUM. 



SAPINDUS MARGINATUS Willdenow. 

 WILD CHINA TREE. 



The wild china tree was found along Las Moras Creek at Fort 

 Clark and on the San Pedro River in Texas, and thence along the 

 Border Line, in the Sonoran Life Zone, to sonth-central Arizona, rang- 

 ing in altitude from 300 to 1,070 meters (about 1,000 to 3,500 feet). 

 It was abundant, forming handsome shady groves in valleys on the 

 headwaters of the Yaqui River and in the Verde Valley of central 

 Arizona. 



RHAMNUS CROCEA NuttaU. 

 EVERGREEN BUCKTHORN. 



This tree was found at Campbell's Ranch at Lagiina, in the Coast 

 Range Mountains. 32.2 km. (20 miles) north of Campo, and on San 

 Clemente Island. This last specimen but slightly resembles Rhamnus 

 insularis Greene. 



RHAMNUS PURSHIANA de Candolle. 

 BEARBERRY; CASCARA BUCKTHORN. 



The bearberry was found in the San Luis, San Jose, and Huachuca 

 mountains, and on the headwaters of the Cajon Bonito Creek near 

 the boundary of Sonora and Chihuahua, Mexico. 



ZIZYPHUS OBTUSIFOLIUS Gray. 

 OBTUSELEAF ZIZYPHUS, 



In Arizona and Sonora this species sometimes becomes a small 

 tree having a trunk 1 to 4 decimeters in diameter and a height of 3 to 

 G meters. The branches are all armed with very long spines. It 

 usually branches from the ground around main trunks, spreading so 

 as to form an impenetrable growth. 



CEREUS GIGANTEUS Engelmann. 

 GIANT CACTUS. 



This, our tallest cactus, bears an edible fruit and attains the height 

 of 12 meters (40 feet). It is known in Arizona and Sonora as the 

 " sahuara." A good picture of it faces page 23 of the Report of the 

 Boundary Commission, published in 1808. As we moved west on the 

 ^Mexican Line this species first appeared in canyons of the Pajaritos 

 Mountains, west of Xogales, near Monument No. 130. It extended 

 we-^tward to the west base of the Gila Mountains, east of the Colorado 

 River. In the lower course of the Santa Cruz Valley, from Tumaca- 

 cori nortliward in Arizona, its range extends farther eastward than 

 on the Boundary Line. It reaches up the Agua Fria Valley of central 



