SN RTE ap E20" BN. 
—— 2 
a 
BAILEY: THE WILD COTTON PLANT IN ARIZONA 305 
seeds and a few had ripened sufficiently to open. By October 26 
in the Santa Rita Mountains many of the bolls had ripened and 
opened, and on November 5, near Globe, they were about half 
opened. The uninjured bolls do not drop off when ripe but stand 
erect and open so that the seeds are gradually scattered by the wind. 
Many plants carry old and empty last year’s bolls. The young 
branches of the plant are herbaceous in appearance and the woody 
stems are rather soft and brittle. One trunk an inch in diameter 
has seven or eight annual rings. 
In places some old plants show evidence of having been grazed 
down by stock during previous seasons. New sprouts have come 
up from the old stumps and the plants are thriving, but the evi- 
dence that stock eat the plant, even down to the woody stems, 
suggests a cause for the present absence of Thurberia from open 
land, and its restricted habitat on steep and usually very rocky 
slopes. In most of the places where I have seen the plant in any 
abundance it was growing among big rocks where cattle could not 
get at it. In this extremely arid region an edible and unarmed 
shrub does not stand much chance where cattle are driven to 
eating many rank tasting and thorny bushes and even the spiniest 
cactus plants. 
From the great abundance of seeds ripened and scattered 
abroad each season it would seem that the plant should reproduce 
itself profusely. That it does not may be due in part to the 
abundance of sparrows which winter in the foothills and are 
eagerly searching for such good sized and edible seeds as Thurberia 
yields, and in part to the numerous mice which probably get 
most of the seeds that the sparrows do not find. 
THE BoLtL WEEVIL 
The weevil was abundant throughout the vertical range of 
Thurberia in Sabino Canyon in the Santa Catalina Mountains 
and in Stone Cabin Canyon in the Santa Rita Mountains. The 
bolls occupied by weevils do not open when they ripen, or dry up, 
and each of these unopened bolls almost invariably contains a 
weevil. 
Many were gathered and brought back in tin cans. No 
weevils were found outside of the bolls which were ripening when 
