1915] 



GREENMAN MONOGRAPH OF SENECIO 609 



rib; stems one to several from a common base, 1.5 to 4 dm. 

 high, striate ; leaves lyrate to pinnately divided into cuneate to 

 subrotund divisions ; inflorescence a terminal corymbose cyme ; 

 heads 5 to 8 mm. high, radiate ; involucre campanulate, slightly 

 calyculate ; bracts of the involucre about 21, linear-lanceolate, 

 3 to 5 mm. long, glabrous ; ray-flowers 8 to 12 ; disk-flowers 45 

 to 60 ; achenes hispidulous. 



Distribution: southern New Mexico, western Texas, and 

 northern Mexico. 



Specimens examined: 



New Mexico : banks of the Rio Grande near El Paso, 

 Wright 1413 (Gray Herb.). 



Texas : valley of the Rio Grande, below Donana, Mexican 

 Boundary Survey, Parry 659 (U. S. Nat. Herb.); El Paso, 

 May, 1881, Vasey (U. S. Nat. Herb.); southeastern Texas, 

 Sept., 1879 to Oct., 1880, Palmer 754 (Gray Herb.). 



Chihuahua : valley of Rio Parral, near Santa Rosalia, 21 

 April, 1847, Gregg 11, (Gray Herb.) co-type; valley near 

 Ortiz, 11 April, 1887, P tingle (Field Mus. Herb.). 



20. S. imparipinnatus Klatt, Natur. Gesell. Halle 15 : 333. 



1881 ; Greenm. Monogr. Senecio, I. Teil, 23. 1901, and in Engl. 

 Bot. Jahrb. 32 : 19. 1902. 



S. lobatus Gray, Syn. Fl. N. Am. I 2 : 394. 1884, and ed. 2. 

 1886, in part, not Pers. ; Coulter, Contr. U. S. Nat. Herb. 2 : 

 241. 1892, in part, not Pers. 



Annual or biennial, glabrous or slightly floccose-tomen- 

 tulose in the axils of the leaves ; stems slender, 1.5 to 4 dm. 

 high, simple or branched from the base; leaves 2 to 10 cm. 

 long, 1 to 3 cm. broad, lyrate to pinnately divided or the lower- 

 most occasionally undivided; the upper stem-leaves remote, 

 sessile, and pinnately divided into small linear and entire to 

 abruptly cuneate and unequally toothed lateral divisions ; in- 

 florescence a terminal few-headed corymbose cyme; heads 6 

 to 8 mm. high, radiate ; involucre campanulate, glabrous, min- 

 utely calyculate; bracts of the involucre usually 21, linear- 

 lanceolate, 3 to 5 mm. long, acute ; ray-flowers 8 to 12 ; disk- 

 flowers commonly 50 to 60 ; achenes hirtellous-puberulent. 



