1908] Grinnell—Biota of the San Bernardino Mountains. 39 
Platanus racemosa Nuttall. 
The sycamore seems to be most thrifty in the Lower Sonoran 
and lower portion of the Upper Sonoran zones. It was common 
in the washes at the mouth of Mill ereek and the Santa Ana river 
canons, and extended up these courses in the open places in 
dwindling size to 3000 feet altitude. 
Purshia glandulosa Curran. 
A common shrub in the pinon brush belt around Doble and 
south to the north base of Sugarloaf up to 7500 feet altitude in 
the sage tract. Noted only on the desert slope of the mountains. 
Adenostoma fasciculatum Hooker & Arnott. 
The chamisal was abundant on the foothills of the Pacific 
_side, extending to as high as 6000 feet altitude on south-facing 
slopes above Clarke’s ranch, Seven Oaks, and to the east of the 
latter point some four miles. 
Amelanchier alnifolia Nuttall. 
The service-berry was abundant at the upper margin of the 
Upper Sonoran zone, and extended a ways into the Transition. 
It is most characteristic of the desert slope of the mountains, 
such as the north base of Sugarloaf and around Gold mountain 
where its abundant fruits were ripening after the 10th of Aug- 
ust. I also saw it on the upper Santa Ana down the Pacific slope 
as low as 5600 feet altitude. 
Cercocarpus betulaefolius Hooker. 
Abundant in the Upper Sonoran brush belt on the Pacifie 
slope of the mountains. It was a conspicuous element in the 
chaparral on the north wall of the upper Santa Ana, as high as 
6000 feet altitude. (See pl. 6.) 
Cercocarpus ledifolius Nuttall. 
The mountain mahogany was a striking and conspicuous fea- 
ture of a certain area on the desert side of the mountains. It 
seemed to occupy a belt of high Upper Sonoran and Lower 
Transition and occurred intermingled with either pinons or 
