242 The Plant World. 



racemes of small flowers are held aloft on the desert slopes, 

 which are held in position for a year, and long after the 

 maturity of the seeds. The location of baking pits above 

 the mescal belt in the Catalina mountains seems to indicate 

 that the Indians have used this plant as food when pressed 

 for supplies. Still a third member of the group is to be 

 seen in Nolina, with its dense tufts of linear leaves a yard 

 long among the rocks on the lower slopes, the inflorescences 

 making great irregular cream-colored plumes, visible for 

 long distances on the mountain sides. 



Woody herbs and other xerophytes. The yellow of 

 the hillsides of the early part of the ye^i' has hardly faded 

 when equally conspicuous clumps of Riddellia cooperi begin 

 to show at the same level and globular clusters of this plant 

 endure for several weeks. A number of other composita- 

 ceous species of less conspicuous aspect abound. 



Of the plants which grow from seed every year, none 

 are more striking that the thistle-poppy {A r gem one inter- 

 media), which affects sandy slopes and washes, the glistening 

 spiny stems and leaves being a grayish-green, a true desert 

 color. A number of buds are developed and one or more 

 are opened every evening on many branches, so that a dis- 

 play of pure white flowers is offered by an individual for a 

 period of 5 or 6 days. 



In the floor-like stretches near the streamways in wide 

 canyons, and over other alluvial areas the canaigre, Riimex 

 hymenosepahis sends up its brown spikes from a heavy thick- 

 ened root which is so heavily loaded with tannin as to make 

 it an object of economic interest. Small ragged irregular 

 clumps of Krameria with purplish flowers are found on the 

 hill-slopes, and give the impression of blossoms arising from 

 dead stems. 



Not many vines show activity during this season, but 

 the Arizona clematis is fairly abundant in the lower plains 

 and its inconspicuous whitish flowers quickly give way to the 

 glistening silverv tailed fruits which are very showy during 

 [line. 



