BAILEY: THE WILD COTTON PLANT IN ARIZONA 303 
its belt are given in the following list. Still others from the upper 
and lower zones overlap and mix with it or extend below or above 
it on colder or warmer nearby slopes. The presence of several 
of the following species is a good indication that Thurberia may 
also occur in the same locality: 
Dasylirion Wheeleri Crossosma Bigelovii 
Quercus oblongifolia Tecoma stans 
Vauquelinia californica Rhus mollis 
Anitsacanthus Thurberi Atriplex angustifolia 
Acacia suffrutescens Aesclepias linearis 
Calliandra erophylla Chrysoma larictfolia 
Erythrina flabelliformis Brickellia californica 
Dodonaea angustifolia Abutilon Lemmoni 
In the Santa Rita Mountains Thurberia is abundant on side 
slopes of Stone Cabin Canyon, mainly on east and west exposures, 
from 4,000 to 4,500 feet. A few scattered plants were found on 
banks along the stony-sided dry wash, but they were most abun- 
dant on steep, open, very stony, east and west slopes. None 
were found on north slopes which otherwise seemed just as suitable 
for it, and there were no real south slopes at this end of the range. 
The almost level plain at the northwest base of the mountains 
comes up to 4,000 feet, which prevents the plant from going lower, 
as it might otherwise do. The plants with which it is most 
closely associated here are mainly the same as in the Santa Catalina 
Mountains. Sotol and the blue oak are invariably with it, but 
also range higher. It is found side by side also with Prosopis 
velutina of Lower Sonoran and Mimosa biuncifera of Upper 
Sonoran, both of which overlap along the edges of the zones. 
Near Globe, north of the Gila Valley, Thurberia is abundant 
with the sotol among big granite boulders on a steep west exposure 
a mile north of the town. It begins near the railroad at the bottom 
of the slope at 3,500 feet and extends up to 3,800 feet. Giant 
cactus grows on adjoining southwest exposures and junipers on 
an adjoining northeast exposure close by at the same level. 
Near Fish Creek Canyon, on the stage road from Roosevelt 
to Phoenix, there is an extensive area of Thurberia which O. F. 
Cook and E. W. Hudson have carefully examined. I went through 
this in the evening when it was too dark to identify many of the 
