1907] Hall. Compositae of Southern California. 219 



other species of the northwest coast extend south to middle Cali- 

 fornia, while many forms belonging to the interior of our north- 

 ern states reach the seacoast only in Southern California. 



7. A. tridentata Nutt., Trans. Am. Philos. Soc. ser. 2, vii. 398 

 ( 1841 ) . SAGEBRUSH. 



Commonly an erect much branched shrub with a distinct 

 trunk and shreddy bark: herbage aromatic, canescent or silvery 

 throughout with a fine and close tomentum : leaves mostly 1.5 to 

 3.5 cm. long, narrowly cuneate, the truncate summit with 3 or 4 

 obtuse teeth or lobes, the uppermost ones linear and entire : pan- 

 icles diffuse, commonly 3 dm. or more long: involucre narrow, 5 

 to 8-flowered, about 4 mm. high ; accessory bracts short, ovate. 



This, the true Sagebrush, ranges from Lower California north 

 along the desert ranges to the high plains of the Great Basin and 

 extends even into Washington and Montana. It is by far the 

 most abundant and best-known shrub in this whole region, in 

 many places forming the principal vegetation of thousands of 

 acres. In Southern California the Sagebrush is abundant on the 

 lower slopes of mountains facing the Colorado and Mohave des- 

 erts, where it occupies the Upper Sonoran Zone and often extends 

 into the Lower Transition. West of the mountains it has been 

 found at the following stations: Descanso, San Diego Co. Mrs. 

 Brandegee; Fallbrook, San Diego Co., Parish; Colton and San 

 Bernardino, Parish; near Riverside Reed, no. 832; and between 

 Glendale and Burbank, near Los Angeles Bmunton, no. 907. 



Var. angustifolia Gray, Proc. Am. Acad. xix. 49 (1883). 

 Leaves all narrower, the lower barely 3-toothed, the upper entire 

 and less than 2 mm. wide. Idaho and the Mohave Desert to 

 southern San Diego Co., ace. to Gray. 



8. A. trifida Nutt., Trans. Am. Philos. Soc. ser. 2, vii. 398 

 (1841). A. tripartite Rydb., Mem. N.Y. Bot. Gard. i. 432 

 (1900). 



A much branched shrub, 2 or 3 to rarely 6 dm. high : herbage 

 silvery or canescent with a very fine close tomentum : leaves about 

 1 cm. long, linear except the dilated upper portion which is cleft 

 or parted into 3 linear lobes ; upper leaves entire : inflorescence 

 contracted, sometimes of simple spikes only a few cm. long ter- 



