CARDUACEAE. 351 



25. XYLORRHIZA Nutt. 



Leaves not spinulose-toothed. 



Leaves spatulate, cuspidate. i. X. venusta. 



Leaves linear-oblanceolate, acute. 2. X. villosa. 

 Leaves spinulose-toothed. 



Ligules 8-10 mm. long. 3. X. coloradensis. 



Ligules 15-20 mm. long. 4. X. Brandegei. 



1. Xylorrhiza venusta (Jones) Heller. (Aster venustus Jones) In dry 

 places in Colo, and Utah. Alt. about 7000 ft. Cimarron ; Hotchkiss. 



2. Xylorrhiza villosa Nutt. (Aster Xylorrhiza T. & G.) In rocky places 

 and clayey soil in Wyo. and Colo. North of Craig, Routt Co. 



3. Xylorrhiza coloradensis (A. Gray) Rydb. (Aster coloradensis A. Gray) 

 In the higher mountains of Colo. South Park. 



4. Xylorrhiza Brandegei Rydb. On high peaks in southern Colo. Alt. 

 12,000 ft. San Juan Pass. 



26. UNAMIA Greene. 



i. Unamia ptarmicoides (Nees) Greene. (Aster ptarmicoides T. & G.) 

 On rocky banks and bluffs from Mass, and Sask. to N. Y. and Colo. Alt. 

 4000-7000 ft. Canon on east side of Cheyenne Mountain ; Horsetooth Moun- 

 tains ; Soldier Canon ; Table Rock. 



27. BUCEPHALUS Nutt. 



Bracts all thin and acute, villous-ciliate on the margins ; style-appendages subulate. 



i. E. Engehnannii. 

 Bracts firmer, merely ciliolate ; the outer obtuse ; style-appendages obtuse. 



Inner bracts acute. 2. E. glaucns. 



All bracts obtuse or mucronate. 3. E. formosus. 



1. Bucephalus Engelmannii (A. Gray) Greene. (Aster Engehnannii A. 

 Gray) In the mountains from Mont, and B. C. to Colo, and Wash. Alt. 

 6000-10,000 ft. Sierra Madre ; Steamboat Springs; Crested Butte; Four-mile 

 Hill, Routt Co.; between Pallas and Sydney; Maclntyre Creek, Larimer Co.; 

 Ruby; Fish Creek Falls; summit of North Park Range, Routt Co. 



2. Bucephalus glaucus Nutt. (Aster glaucus T. & G.) In the mountains 

 of Wyo., Colo, and Utah. Alt. 7000-10,000 ft. Headwaters of Clear Creek; 

 Gray's Peak ; Bosworth's ranch ; Black Canon ; Durango ; chaparral-covered 

 hills southeast of Ouray; about Ouray; Grand Lake; Home; Pagosa Springs; 

 mountains between Sunshine and Ward ; Roaring Fork, Larimer Co. 



3. Bucephalus formosus Greene. In the mountains of Colo. Alt. about 

 9500 ft. Near Pagosa Peak. 



28. ASTER L. 



Involucres and peduncles glandular. 



Bracts narrowly linear, almost equal in length. I. CAMPESTRES. 



Bracts thick, oblanceolate, well imbricated. II. OBLOXGIFOLII. 



Involucres and peduncles not glandular. 



Outer bracts neither foliaceous nor equalling or surpassing the inner. 

 Bracts more or less pubescent on the back. 

 Bracts not bristle-pointed. 



Heads solitary ; plant less than 3 dm. high ; leaves oblanceolate or the 



upper linear. III. ALPIM. 



Heads corymbose or paniculate. 



