FLOWERING PLANTS AND FERXS OF ARIZONA 993 



5. Dvssodia papposa (Vent.) Hitchc, Acad. Sci. St. Louis Trans. 5: 



503. 1891. 



Tagetes papposa Vent.. PI. Jard. Cels. pi. 36. 1801. 

 Boebera papposa. Rydb. ex Britton. Manual 1012. 1901. 



Coconino. Gila. Cochise, and Santa Cruz Counties. 4.500 to 7.000 

 feet, roadsides and waste places, September and October. Illinois 

 to Montana, south to Louisiana and Arizona. 



6. Dvssodia thurberi (A. Gray) Robinson, Amer. Acad. Arts and Sri. 



Proc. 49: 508. 1913. 



Hymenatherum thurberi A. Gray. ibid. 19: 41. 1883. 

 ThymophyUa thurberi Woot. and Standi., Contrib. U. S. Natl. 

 Herbarium 16: 191. 1913. 



Grand Canyon (Coconino County) and northern Mohave County 

 to Pima and Yuma Counties, 3.500 feet or lower, dry rocky slopes and 

 mesas, April to October. Texas to southern Nevada, southeastern 

 California, and northern Mexico. 



7. Dyssodia hartwegi (A. Grav) Robinson, Amer. Acad. Arts and Sci. 



Proc. 49: 507. 1913." 



Hymenatherum harticegi A. Gray, PL Wright. 1: 117. 1852. 

 ThymophyUa pringlei Rydb., North Amer. Fl. 34: 177. 1915. 



Chiricahua Mountains. Cochise County, about o.oOO feet, on 

 limestone, September to October. Southeastern Arizona to central 

 Mexico. 



8. Dvssodia pentachaeta (DC.) Robinson, Amer. Acad. Arts and Sci. 



Proc. 49: 507. 1913. 



Hymenatherum pe ntachaetum DC, Prodr. 5: 642. 1836. 

 ThymophyUa pentachaeta Small, Fl. Southeast. U. S. 1295. 



1903. 

 ThymophyUa gracilis Rydb., North Amer. Fl. 34: 176. 1915. 



Lees Ferry and Grand Canyon (Coconino County), near Tucson 

 (Pima County), 2.500 to 3.500 feet, dry slopes and mesas, March to 

 October. Texas to Arizona and northern Mexico. 



104. POROPHYLLUM 



Glabrous herbs or suflrutescent perennials; leaves opposite or 

 alternate, with conspicuous translucent oil glands in the tissue; beads 

 medium -sized, discoid, whitish or purplish; phyllaries 5 to 8. linear or 

 oblong, 1-seriate, equal, free, with conspicuous linear oil glands, 

 without accessory bractlets; achenes slender, elongate: pappus of 

 copious free capillary bristles. 



P. gracile, called yerba-del-venado by the Mexicans, is said to be 

 relished by deer and cattle, notwithstanding the strong, unpleasant 

 odor of the plant. 



Key to the species 



1. Annual: leaf blades oval, thin, mostly 2 to 4 cm. long, on slender petioles about 

 as long as the blades; peduncles thickened toward the apex; heads 2 to 2.5 



Cm. high _. _ 1. P. MACROCEPHALTJM. 



1. Perennial, more or less woody toward the base: leaves filiform to narrowly 

 linear, sessile; peduncles not noticeably thickened toward the apex: heads 

 1.5 to 2 cm. high * 2. P. c.r.uile. 



