1907] Hall. Compositae of Southern California. 165 



many-flowered. Involucral bracts in a single series, the margins 

 overlapping, faintly keeled externally, shallowly grooved on the 

 inner surface, the groove being occupied by the outer edge of 

 the ray-achene. Disk-flowers numerous, yellow, 4-toothed. Rays 

 short, white or yellow. Achenes flat with ciliate or cartilaginous 

 margins. Pappus a squamellate or cupulate crown and often a 

 slender awn from one or both of the angles. 



1. P. Emoryi Torr., Emory's Kept. N. Mex. 142 (1848) ; Rose, 

 Bot. Gaz. xv. 116 (1890). P. nuda Torr., Pacif. R. Rept. iv. 100 

 (1857). P. California Gray, Syn. Fl. i. pt. 2, 321 (1884), in 

 part ; not P. Calif ornica Benth. P. Greenei Rose, Bot. Gaz. xv. 

 117 (1890). 



Three to 6 dm. high, the striate stems freely branching and 

 widely spreading from an annual or more enduring root : herbage 

 viscid and glandular-pubescent throughout and also somewhat 

 short-hirsute, or glabrate below, ill-scented: leaves roundish or 

 cordate in outline, incisely 5 to 9-lobed or -cleft, the divisions 

 acutely few-toothed ; lower leaves 1.2 cm. long on petioles of equal 

 length ; upper smaller, often nearly sessile : peduncles 1 to 4 cm. 

 long: heads 7 mm. high: outer involucral bracts oblong, acute, 

 ciliate ; inner bracts narrower, scarious-margined : rays about 12. 

 2 or 3 mm. long ; all the corollas glandular-pubescent : style- 

 branches with short minutely hirsute appendages: achenes flat, 

 oblong to subclavate, black, smooth and shining or rarely puberu- 

 lent on the sides, hispid-ciliate on the margins : pappus an incon- 

 spicuous erose or lacerate crown and a single slender awn about 

 as long as the achene, or the awn usually wanting. 



Lower and Upper Sonoran zones : near Santa Monica, Hasse; 

 Catalin* Island, Davidson; San Clemente Island, Nevin & Lyon, 

 ace. to Rose; San Diego, Hall; throughout the Colorado Desert, 

 various collectors ; Newberry, in the southern part of the Mohave 

 Desert; Panamint Mts. (in the epappose form); Arizona and 

 Mexico. 



Often forming dense clumps 5 to 10 dm. in diameter, covered 

 with a profusion of flower-heads, in which the yellow disks are 

 sometimes as conspicuous as the white rays. Some specimens 

 have been referred to P. microglossa (=P. acmella of Bot. 



