1907] Hall. Compositae of Southern California. 35 



1. G. lucida Greene, Fl. Fr. 361 (1897). Xanthocephalum 

 lucidum Greene, Pitt. ii. 282 (1892). Gutierrezia Euthamiae 

 microcephala Gray, Syn. Fl. i. pt. 2, 115 (1884), in part. 



Straggling bush, 3 dm. or more high: herbage very resinous 

 and of a clear yellowish-green color: foliage sparse and lax: 

 inflorescence cymose-paniculate ; the numerous heads glomerate 

 at the ends of the slender twigs : involucre narrow, 3 mm. high ; 

 bracts closely appressed, with obscure greenish tips. 



Confined chiefly to dry hills of the Mohave Desert (and south- 

 ward?) : Indian Wells, Kern Co., M. A. Knapp; Cottonwood 

 Creek, Inyo Co., Purpus, no. 3025; Santa Monica Range, Hasse. 

 ace. to Parish. 



2. G. Sarothrae (Pursh) Britton & Rusby, Trans. N. Y. Acad. 

 vii. 10 (1887). Solidago Sarothrae Pursh, Fl. 540 (1814). 

 Brachyris Euthamiae Nutt., Gen. ii. 163 (1818). Gutierrezia 

 Euthamiae T. & G., Fl. ii. 193 (1841). G. divergens Greene, 

 Pitt. iv. 58 (1889), in part. 



Bushy plant with numerous erect stems from a woody base, 

 3 to 6 dm. high: inflorescence cymose-paniculate; heads short- 

 peduncled or sometimes in terminal glomerules of 3 to 5 : invo- 

 lucre clavate-oblong, 3 or 4 mm. high ; bracts with minute green 

 tips : disk and ray-flowers each 3 to 7 : achenes sericeous-pubescent. 



Arid plains and rocky hills of the Upper (and Lower?) 

 Sonoran Zone almost throughout western North America and by 

 far the most abundant species in our district: San Fernando 

 Valley, Barber, no. 170 ; San Jacinto Mts., Vandeventer, no. 10 ; 

 Jamul Valley, San Diego Co., Palmer, no. 127; Mission Valley. 

 San Diego, Oct. 1, 1883, Orcutt, no. 991. 



3. G. Californica (DC.) T. & G., Fl. ii. 193 (1842). Brachy- 

 ris California DC., Prodr. v. 313 (1836). G. divergens Greene, 

 Pitt. iv. 58 (1899), in part. 



Stems more loosely branched above than in G. Sarothrae: 

 heads larger and broader, hence obovate-turbinate, mostly scat- 

 tered in the panicles or in an open cyme (rarely somewhat glom- 

 erate) : involucre 4 or 5 mm. high and fully as broad at the 

 summit : bracts with conspicuous green tips, the inner ones very 

 obtuse : achenes densely silky. 



