WOOTON AND STANDLEY PLOEA OF NEW MEXICO. 671 



New Mexico: Tuiiitcha Mountains; Cedar Hill; Dulce; Cliama; Sandia Moun- 

 tains; Santa Fe and Las Vegas mountains; Johnsons Mesa; Middle Fork of the Gila; 

 Kingston; Burro Mountains; Water Canyon; San Luis Mountains; Organ Mountains; 

 White and Sacramento mountains. Open slopes and in thickets, chiefly in the 

 Ti'ansition Zone. 



29. PETRADORIA Greene. 



Low tufted perennials with mostly basal narrow rigid sharp-pointed leaves and 

 small heads of yellow flowers in corymbs; heads narrowly oblong, 5 to 8-flowered, 

 with 1 to 3 short rays; bracts much imbricated, firm, broad, slightly carinate, with 

 small green tips; achenes compressed, 5-nerved, with short rigid jjai^pus. 



KEY TO THE SPECIES. 



Basal leaves linear-oblanceolate, with 3 or more UBrves, long, usually 

 more than half as long as the stems; plants usually 20 cm. high 

 or more 1. P. pumila. 



Leaves all linear, 1-nerved, short, less than half as long as the stems, 



more numerous; plants lower 2. P. graminea. 



1. Petradoria pumila (Terr. & Gray) Greene, Erythea 3: 13. 1895. 

 Solidago pumila Torr. & Gray, Fl. N. Amer. 2: 210. 1840. 



Type locality: "In open situations, on shelving rocks tov/ard the western declivity 

 of the Rocky Mountains." 



Range: Wyoming and Nevada to Colorado and New Mexico. 



New Mexico: Abiquiu; Pecos River; Rio Zuni; Farmington; Carrizo Mountains. 

 Dry hills and plains, in the Upper Sonoran Zone. 



2. Petradoria graminea Woot. & Standi. Contr. U. S. Nat. Herb. 16: 183. 1913. 

 Type locality: Northwestern New Mexico. Type collected by C. C. Marsh (no. 



209). 



Range: Northwestern New Mexico. 



New Mexico: Gallup; Tunitcha Mountains. Plains and low hills, in the Upper 

 Sonoran Zone. 



30. BACCKARIS L. 



Often viscid shrubs, rarely perennial herbs, with alternate, simple, entire or toothed 

 leaves, the branches commonly striate or angled; heads usually small, whitish or 

 yellowish, dioecious; involucre of small, much imbricated, mostly acute bracts; recep- 

 tacle usually flat and naked; papj^us of fertile flowers of numerous bristles in 1 or 

 several series, often elongated in fruit. 



KEY to the species. 



Pappus scant, little if at all elongated in fruit, not exceeding the 

 styles. 

 Bracts with green midribs; leaves linear or oblong, rather 



obtuse, 1-nerved, 4 cm. long or less 1. B. bigelovii. 



Bracts yellowish throughout; leaves elongated-lanceolate, 



acute, 3-nerved at the base, 4 to 10 cm. long 2. B. glulinosa. 



Pappus abundant, much elongated in fruit and exceeding the 

 styles. 

 Pappus in several series; plants 50 cm. high or less, herbaceous 



to the base 7. B. wrightii. 



Pappus in a single series; plants usually 1 meter high or more, 

 shrubby. 



