1907] HallCompositae of Southern California. 163 



elongated-cylindraceous, with very short proper tube and short 

 externally glandular-bearded teeth. Style-branches truncate- 

 capitate. Achenes narrow, terete, obscurely nerved or angled. 

 Pappus of 4 to 6 hyaline paleae. 



De Candolle's Psilostrophe dates from 1838, whereas Nuttall's 

 Eiddellia, a better-known name for the same genus, dates from 

 1841. By the rule of priority, Psilostrophe is therefore the name 

 to be retained. 



1. P. Cooperi (Gray) Greene, Pitt. ii. 176 (1891) ; A. Nelson, 

 Proc. Biol. Soc. Wash. xvi. 20 (1903). Riddellia Cooperi Gray. 

 Proc. Am. Acad. vii. 358 (1868). 



Shrubby at base, the rounded clumps about 5 dm. high : herb- 

 age white with a densely pannose tomentum: leaves linear or 

 narrowly spatulate and obtuse, entire, 1 to 5 cm. long, green and 

 glabrate in age : heads scattered, on evident peduncles : involucre 

 5 to 7 mm. high ; bracts 15 to 30, the inner ones much softer than 

 the rigid and oblong outer ones : rays 4 to 8, broadly oval, 1 or 2 

 cm. long, shallowly 3-lobed at the broad ape: pappus-paleae 

 oblong or lanceolate, entire to erose-laciniate, shorter than the 

 achene. 



Lower Sonoran Zone: Chuckawalla Bench, Colorado Desert, 

 in Riverside Co., Sckellenger, no. 24, and Hall, no. 5890 ; Provi- 

 dence Mts., Mohave Desert, Brandegee; Arizona ; Nevada ; Lower 

 California. 



62. BAILEYA Harv. & Gray. 



Densely white-woolly erect annuals or perennials of the Desert 

 Area. Lower leaves pinnatifid, the upper entire, all alternate. 

 Heads solitary, on conspicuous peduncles. Involucre of numer- 

 ous distinct densely floccose bracts. Ray-flowers pistillate ; ligules 

 yellow and showy when young, becoming papery and reflexed in 

 age. Disk-flowers numerous, fertile, the corolla gradually ex- 

 panding above the short proper tube, the teeth bearded. Style- 

 branches short, obtuse. Achenes oblong or clavate, truncate at 

 the obscurely toothed apex, conspicuously pluristriate. Pappus 

 none. 



Eays 5 to 8: peduncles under 3 cm. in length 1. B. pauciradiata. 



Bays 25 to 50 : peduncles often much elongated 2. B. multiradiata. 



