398 CARDUACEAE. 



Richardson) In wet wooded places from N. D. and Mont, to N. M. and 

 Ariz. Alt. 6000-10,000 ft. Four-Mile Hill, Routt Co.; Pandora; Ute Pass; 

 Chambers' Lake ; mesa near Yampa ; Green Mountain Falls ; Parlin ; Ruxton 

 Park; Parrott City; Gunnison; near Pagosa Peak; Steamboat Springs; near 

 Colorado Springs ; Sangre de Cristo Creek ; Silver Plume ; La Veta ; Ward ; 

 Spring Canon ; Georgetown ; above Beaver Creek ; canon west of Palmer 

 Lake ; Hotchkiss ; headwaters of Clear Creek. 



63. Senecio filifolius Nutt. (S. Doitglasii A. Gray, in part; not DC.) In 

 valleys from Colo, and Utah to Tex. and Ariz. ; also in Mex.- Florence ; 

 Westcliffe; Estes Park, Larimer Co.; Canon City; Pueblo. 



64. Senecio Riddellii T. & G. (S. filifolius Fremontii T. & G. ; A. Dou- 

 glasii A. Gray, in part; 5". Fremontii Rydb. ; not T. & G.) On plains and in 

 valleys from Neb. and Colo, to Tex. and N. M. Alt. 4000-6000 ft. Brantly 

 Canon; Boulder; Ft. Collins; Cimarron and Squaw Hill. 



65. Senecio multicapitatus Rydb. On plains and in valleys from Colo, 

 to N. M. and Ariz. Alt. 7000-11,000 ft. Huerfano Valley, near Gardner; 

 Mt. Princeton Station. 



66. Senecio spartioides T. & G. (S. Douglasii A. Gray, in part) On plains 

 and in valleys from Neb. and Wyo. to Tex. and Ariz. Alt. 4000-9500 ft. 

 Ft. Collins ; Idaho Springs ; Engelmann Canon ; along the Uncompahgre 

 River, near Ouray ; Gunnison ; Salida ; Cucharas Valley, near La Veta ; Pike's 

 Peak; Antonito; Empire; mountains between Sunshine and Ward; Rist 

 Canon; Cache la Poudre River; Buena Vista; Golden; Colorado Springs. 



87. TETRADYMIA DC. 



Shrub not spiny. 



Primary leaves oblanceolate. i. T. incrmis. 



Primary leaves linear. 2. T. linearis. 



Shrub spiny. 3. T. spinosa. 



1. Tetradymia inermis Nutt. Dry hills from Mont, to Colo, and Nev. 

 Alt. 4000-9000 ft. Gunnison ; North Park, Larimer Co. ; La Veta ; Cerro 

 Summit ; Leroux Creek ; North Fork, Larimer Co. 



2. Tetradymia linearis Rydb. On dry hills and plains of Colo, and Utah. 

 Alt. about 7700 ft. Gunnison ; La Veta. 



3. Tetradymia spinosa H. & A. On dry hills and plains from Mont, and 

 Ore. to Colo, and Nev. Alt. 4500-7000 ft. Mancos ; near Wyoming line, 

 Routt Co. ; Hotchkiss ; Mancos Canon ; Grand Junction ; Palisades. 



Tribe 9. CYNAREAE. 



88. CARDUUS L. THISTLE. 



Bracts of the involucres conspicuously arachnoid-pubescent, neither reflexed nor 



spreading, except the tips. 



Inner bracts with conspicuously dilated tips. I. VIRIDIFLORI. 



Inner bracts long-attenuate, rarely slightly dilated. II. ERIOCEPHALI. 



Bracts of the involucres not arachnoid or only slightly so on the margins, 

 Bracts not with a dorsal glandular ridge. 



Bracts, except the outermost, with dilated fimbriate tips. 



III. CARLINOIDES. 

 Bracts, except the innermost, not with dilated tips. 



Bracts not squarrose, except the spines or the loose tips. 



