344 CARDUACEAE. 



4. Sideranthus spinulosus (Pursh) Sweet. (Aplopappus spinulosus DC.) 

 On dry plains and prairies from Minn., Sask. and Mont, to Tex. and Ariz. 

 Alt. 4000-7000 ft. Cheyenne Mountain ; Denver ; Arboles ; Manitou ; Ft. Col- 

 lins ; Cucharas Valley, near La Veta; Greeley; Canon City; New Windsor; 

 Spring Canon; Hotchkiss; Boulder; roadside near Rocky Ford; Ft. Collins; 

 Wray; Raton Range. 



5. Sideranthus glaberrimus Rydb. On dry plains from S. D. and Wyo. 

 to Ind. Terr, and Colo. Table Rock. 



6. Sideranthus puberulus Rydb. On dry hills in Colo. Alt. up to 8000 ft. 

 Salida; Buena Vista. 



7. Sideranthus gracilis (Nutt.) Rydb. (A. gracilis A. Gray) On dry 

 hills from Colo, and Utah to Tex. and Ariz. ; also in Mex. Alt. about 6700 

 ft. Durango; between Porter and Durango ; Mancos. 



12. PYRROCOMA Nutt. 



Bracts except the innermost obtuse, obovate or oblong. i. P. crocea. 



Bracts mostly acute or acuminate. 



Heads large ; disk 2 cm. or more in diameter ; bracts in about 3 series. 



Upper part of stem and involucre decidedly villous ; bracts wholly foliaceous. 



2. P. dementis. 



Stem and involucre almost glabrous ; bracts chartaceous at the base, with 

 foliaceous tips. 3. P. ititegrifolia. 



Heads smaller ; disk less than 2 cm. in diameter. 

 Bracts in 2-3 unequal series. 



Stem and bract more or less white-woolly. 4. P. lagopus. 



Stem and bracts glabrous or nearly so. 5. P. Vaseyi. 



Bracts nearly of the same length. 



Plant villous. 6. P. inuloides. 



Plant, except the upper parts, glabrate in age. 7. P. uninora. 



1. Pyrrocoma crocea (A. Gray) Greene. (Aplopappus croceus A. Gray) 

 In the mountains from Wyo. to N. M. and Ariz. Alt. 5000-8000 ft. Doyle's ; 

 Cerro Summit; North Park; La Plata Canon; Steamboat Springs; between 

 Pallas and Sydney ; Egeria Park ; Little Muddy ; Gunnison Co. ; Walton 

 Creek; Boulder; North Park, along the Michigan; Willow Creek, Routt Co. 



2. Pyrrocoma dementis Rydb. In the mountains of Wyo. and Colo. 

 Tennessee Pass ; Robinson ; Mt. Harvard. 



3. Pyrrocoma integrifolia (Porter) Greene. (Aplopappus integrifolius Por- 

 ter) In the mountains from Sask. and B. C. to Colo. Rabbit-Ear Range. 



4. Pyrrocoma lagopus Rydb. On dry plains and alkali flats in Wyo. and 

 Colo. North Park. 



5. Pyrrocoma Vaseyi (Parry) Rydb. (Aplopappus lanceolatus Vaseyi 

 Parry) In the mountains from Wyo. to Colo, and Utah.- Alt. up to 9000 

 ft. Middle Park ; Lake John, North Park ; North Fork, Larimer Co. 



6. Pyrrocoma inuloides (Hook.) Greene. (Aplopappus inuloides Nutt.) 

 Plains from Mont, and Ida. to Colo. North Park, near edge of Wyoming. 



7. Pyrrocoma uniflora (Hook.) Greene. (Aplopappus uniflorus Nutt.) In 

 river valleys from Sask. and Mont, to Colo, and Utah. 



13. OONOPSIS Greene. 



Dwarf; stem less than i dm. high; heads 6-10 dm. high. i. O. Engehnannii. 

 Plant robust, 1.1-3 dm. high; heads 15-20 mm. high. 



