621 Rydberg : Studies on the Rocky Mountain Flora 



The species is not uncommon on barren hills and in bad-lands, 

 up to an altitude of 1500 m. Its range extends from Saskat- 

 chewan and western Nebraska to Colorado and Arizona. 



2. Sideranthus rubiginosus (Torr. & Gray) Britton 

 Aplopappus rubiginosum Torr. & Gray, Fl. N. Am. 2 : 240. 

 1842. 



Eriocarpiini riibiginos2ini (Torr. & Gray) Britton, Mem. Torr. 

 Bot. Club, 5: 316. 1894. 



The species was first described as a perennial. Our plant is 

 evidently only annual. Possibly two different species have been 

 confused under the name E. rubiginosinn. It grows in sandy soil 

 from Texas to Colorado and western Nebraska, reaching an alti- 

 tude of 1500 m. 



3. Sideranthus australis (Greene) 



Eriocarpwn aiistrale Greene, Erythea, 2: 108. 1894. 



This grows on the plains of western Texas, Colorado, New 

 Mexico and Mexico. 

 4. Sideranthus spiNULOsus (Pursh), Sweet, Hort. Brit. 227. 1826 



Avielliis spimilosus Pursh, Fl. Sept. Am. 564. 18 14. 

 Sideranthus pinnatifidus Fraser; Pursh, Fl. Am. Sept. 750. 1 8 14 

 Aplopappus spimdosus DC. Prod. 5 : 347. 1836. 

 Eriocarpum spinulosiini {Vuvsh) Greene, Erythea, 2: 108. 1894. 

 The species is rather common on plains and dry prairies, from 

 Saskatchewan, Nebraska and Texas to Mexico, Arizona and Idaho. 



5. Sideranthus glaberrimus sp. no v. 



Perennial, with a short woody caudex, perfectly glabrous, or 

 very sparingly glandular-puberulent. Stems several, branched 

 above, very leafy, 1-3 dm. high : leaves rather rigid, about 2 cm. 

 long, bluish green, glabrous, pinnatifid ; segments oblong, 2-5 mm. 

 long and i mm. or less wide, spinulose-tipped : heads numerous, 

 corymbose, depressed hemspherical, 8-10 mm. high and 8-15 mm. 

 broad : bracts imbricated in 6-7 series, the outer gradually shorter, 

 firm, appressed, with a herbaceous tip, acute ; the inner tinged with 

 purplish : rays about 20, 4-5 mm. long and about i mm. wide. 



The species is closely allied to the preceding, differing mainly 

 in the total lack of tomentum, even when young, the bluer color 

 and the smaller, generally purple-tinged bracts. It grows on 

 plains and hills, from Iowa and Indian Territory to New Mexico 

 and Wyoming. 



