1907] HallCompositae of Southern California. 183 



each bearing a solitary head: involucre usually 5 mm. high (4 to 

 6 mm.) ; its rigid carinate bracts about 8, either distinct to the 

 base or lightly united for about two-thirds the way up into a 

 campanulate cup with ovate acute teeth : receptacle acutely coni- 

 cal, varying from chaffy to scrobiculate : rays about 5 to 10, yel- 

 low, 4 to 10 mm. long : disk-corollas funnel-form with a short 

 cylindric glandular tube : anther-tips ovate, merely acute : style- 

 branches conical, acute : achenes linear, pubescent with appressed 

 hairs : pappus commonly a mere crown of quadrate erose scales, 

 sometimes conspicuous and lacerate, sometimes quite obscure or 

 wanting. 



Confined to the Desert Area and surrounding mountains, from 

 Palm Springs, Riverside Co., to Fort Tejon, Kern Co., and Owens 

 Valley, Inyo Co. 



It would not be difficult to segregate a number of species from 

 the aggregate E. ambiguum if one had only the extreme forms. 

 An abundance of material shows, however, that species based on 

 length and number of rays, union or separation of involucral 

 bracts, character of pappus, and presence or absence of chaff on 

 the receptacle, are neither natural nor of scientific value. Not 

 only do these characters vary greatly, but they may be found in 

 almost all possible combinations, the variations not being con- 

 commitant. 



The original Lasthenia ambigua had united bracts, a "scrobic- 

 ulate, rarely smooth" receptacle, and a coroniform pappus of 

 short erose-truncate paleae. It came from near Fort Tejon, 

 where I have recently re-collected it under no. 6297. 



A similar form but with the bracts distinct and the rays 

 hardly longer than the disk was described as Bahia parviflora 

 from specimens gathered at the same station. It has not been 

 re-collected. 



E. paleaceum was based on specimens gathered at Kernville 

 and Olancha. It combines distinct bracts, developed rays, and 

 a short paleaceous pappus, with a chaffy receptacle, the upper 

 paleae of which are persistent and become 1 mm. long. Exactly 

 the same form, except that the paleae of the receptacle are usual- 

 ly less numerous and smaller or quite obscure, is common in good 

 seasons from the Argus and Panamint Mts. south to Fremonts 



