STANDLEY TEEES AND SHEUBS OF MEXICO 1505 



15. Baccharis potosina A. Gray, Proc. Amer. Acad. 15: 33. 1879. 



Coahuila and San Luis Potosi; type from San Luis Potosi. 



Suffrutescent, glutinous, much branched, 50 cm. high or more, the slender erect 

 branches striate; leaves linear to narrowly linear-oblanceolate or linear-lanceolate, 

 2 to 4.5 cm. long, 1 to 3 mm. wide, 1-nerved, acute or acuminate, entire or some- 

 times with a few small acute teeth above; heads from solitary at tips of the 

 numerous branches to loosely cymose-panicled or rather closely panicled, always 

 rather numerous, 3 to 7 mm. high; achenes 5-nerved, glabrous; pappus 4 mm. 

 long. 



16. Baccharis occidentalis Blake, Contr. U. S. Nat. Herb. 22: 595. 1924. 

 Tepic and Jalisco; type from Guadalajara, Jalisco. 



Stems numerous, 60 to 80 cm. high, slender, junciform, glabrous, striate, not 

 distinctly viscid, herbaceous almost throughout; leaves chiefly below the middle 

 of stem, linear to very narrowly linear-lanceolate or oblanceolate, 2.5 to 5 cm. 

 long, 1.5 to 4 mm. wide, entire or with a few slender acute teeth above, weakly 

 triplinerved; achenes glandular, 5-nerved; pappus about 7 mm. long. 



17. Baccharis squarrosa H. B. K. Nov. Gen. & Sp. 4: 67. 1820. 

 Baccharis seemanni A. Gray, Proc. Amer. Acad. 15: 33. 1879. 



Sierra Madre of northwestern Mexico, Guanajuato, and San Luis Potosi; type 

 collected near Guanajuato. 



Stems subsimple, about 40 cm. high, striate, somewhat glutinous, herbaceous 

 nearly to base; leaves linear-lanceolate or linear, 2 to 5.5 cm. long, 2 to 4 mm. 

 wide, entire, weakly triplinerved; heads 1 to 4, 1 to 1.2 cm. high, long-peduncled; 

 involucre 7 to 9 mm. high, the phyllaries with broad green midline; achenes 

 glandular, 5-ribbed; pappus (immature) 7 mm. long, scarcely exceeding the styles. 



18. Baccharis brachyphylla A. Gray, PL Wright. 2: 83. 1853. 



Sonora. California and Arizona; type collected between Conde's Camp and 

 the Chiricahua Mountains, Arizona. 



Suffrutescent, 1 meter high or less, much branched, densely and finely puberu- 

 lous; leaves linear or oblong-linear, entire, 1.5 cm. long or less; heads numerous, 

 in rather open panicles; involucre 3 to 6 mm. high; achen(!s 5-nerved, glandular- 

 pilosulous; pappus about 7 mm. long. 



19. Baccharis elegans H. B. K. Nov. Gen. & Sp. 4: 60. pi. 32J,. 1820. 

 Baccharis oligantha Schultz Bip.; Klatt, Leopoldina 20: 91. 1884, as synonym. 

 Puebla and Oaxaca; type locality unknown. 



Glutinous shrub 1 meter high or less; leaves oval or oblong, 1.3 to 3 cm. long, 

 6 to 18 mm. wide, short-petioled, closely sharp-serrate or serrulate, veiny, barely 

 triplinerved; panicles rounded, many-headed; involucre 2.5 to 5 mm. high; 

 achenes 5-nerved, essentially glabrous; pappus 5 mm. long. 



20. Baccharis bigelovii A. Gray in Terr. U. S. & Mex. Bound. Bot. 84. 1859. 

 Sonora to Coahuila; type from Puerto de Paysano, Sonora. Texas and New 



Mexico. 



Similar to B. elegans; leaves cuneate or cuneate-oblong to oblong-oblanceolate, 

 1.5 to 3.5 cm. long, 4 to 15 mm. wide, 1-nerved or obscurely triplinerved, not 

 venose, rather coarsely toothed. 



21. Baccharis alamosana Blake, Contr. U. S. Nat. Herb. 22: 595. 1924. 



Known only from the type locality. Sierra de Alamos, Sonora. 



Frutescent, somewhat glutinous, slender, 40 cm. high and more; leaves lance- 

 olate, 1.8 to 3.5 cm. long, 4 to 9 mm. wide, petioled, finely serrulate, acuminate; 

 pistillate heads tiny, in small cymose panicles; involucre about 2.5 mm. high; 

 achenes 5-angled, glabrous; pappus 2.5 mm. long. 



