1907] Hall. Compositae of Southern California. 225 



1. P. ramosissima (Torr.) Gray, Proc. Am. Acad. vii. 363 

 (1868). Tetradymia ramosissima Torr., in Emory Kept. 145 

 (1848). 



Stem suffrutescent at base and persistent for at least one 

 year: much branched and densely leafy forming a compact 

 rounded plant 15 cm. or less high and 5 to 20 cm. across : herbage 

 white with a dense close tomentum, strongly scented with a tur- 

 pentine-like odor : leaves thick, coarsely and irregularly toothed, 

 subcordate or tapering into the stout petiole : peduncles either 

 short and erect or longer and recurved, so that the heads always 

 remain embedded in the dense foliage : involucre 6 or 7 mm. high ; 

 outer bracts broadly oblong, obtuse, the broad tips somewhat 

 spreading or recurved ; inner bracts narrower, sometimes acutish : 

 corollas yellow or purplish : achenes short-turbinate. 



Lower Sonoran Zone: Borregos Springs, Colorado Desert. 

 Brandegee; near Palm Springs, Colorado Desert, Schellenger, no. 

 40 ; Sheephole Mts., Mohave Desert, Hall & Chandler, no. 6071 ; 

 Panamint Valley, Inyo Co. ; east into Arizona, south into Lower 

 California. Very common on ledges of rocks and in stony soil 

 on the Colorado Desert of eastern Riverside and Imperial coun- 

 ties. 



2. P. annua (Nutt.) Gray, PL Wright, ii. 100 (1853). Bul- 

 bostylis annua Nutt., Journ. Phila. Acad. n. ser. i. 179 (1848). 



Root strictly annual : stem loosely branched, the branches 

 ascending, 5 to 15 cm. high : herbage with a scurfy tomentum : 

 leaves short-cuneate at base, coarsely and irregularly dentate, the 

 small often entire ones of the inflorescence carried beyond the 

 heads by their petioles : peduncles very short, commonly reflexed 

 in age : involucre 7 to 9 mm. high ; bracts ovate-oblong to linear- 

 lanceolate, usually acute, all erect and the outer ones not larger 

 than the inner : corollas pale yellow or purplish : achenes oblong- 

 turbinate : pappus less copious than in no. 1. 



Lower Sonoran Zone: alkaline soil near Rabbit Springs, 

 southern Mohave Desert, Parish, no. 1260: Red-rock Canon, east- 

 ern Kern Co., Hall & Chandler, no. 7375 ; Owens Valley ; east to 

 Utah and Arizona. 



