190 ROSACEAE. 



22. SOSA L. Rose, Brier. 



Infrastipular spines not present. 

 Stems bristly or prickly. 



Flowers corymbose at the end of the stems or of almost erect branches. 



Leaf-blades glabrous ; stipules, leaf-stalks and sepals more or less glandular. 



1. R. arkansana. 

 Leaf-blades densely pubescent, at least beneath. ;;. R. pratincola. 



Flowers solitary at the ends of spreading branches. 

 Leaflets finely but distinctly pubescent beneath. 



Leaflets rather firm, coarsely serrate ; fruit spherical or nearly so. 



3. R. Sayi. 

 Leaves thin, sharply serrate ; fruit elongated-ellipsoid. 



4. R, Engelmannii. 

 Leaflets glabrous ; fruit rounded-obovate or spherical. 5. R. melina. 



Stem unarmed. 11. i?. Bakeri. 



Infrastipular spines present. 



Hypanthium and fruit bristly. 6. R. Underwoodii. 



Hypanthium and fruit glabrous. 

 Leaflets glabrous or nearly so. 

 Spines curved. 



Leaflets 1-2 cm. long ; spines stout ; fruit i cm. or less in diameter. 



7. R. manca. 

 Leaflets 2-3.5 cm. long; fruit 1-1.5 cm. in diameter. 



Spines slender ; leaves not bluish green, thin. 8. R. melina. 



Spines stout ; leaves bluish green, thick. 9. R. pandorana. 



Spines straight or nearly so. 10. R. Macounii. 



Leaflets decidedly pubescent beneath. 



Fruit over i cm. broad ; leaflets large ; flowers solitary ; spines stout. 



II. J?. Bakeri, 

 Fruit less than i cm. broad ; spines weak, slightly curved or straight ; flowers 

 often corymbose. 

 Petioles and stipules densely glandular. 12. R. Fendleri. 



Petioles not glandular ; stipules merely glandular-toothed or entire. 

 Spines very slender and straight. 13. 7?. aciculata. 



Spines stouter and somewhat curved. 14. R. Maximilliani, 



1. Rosa arkansana Porter. In the Arkansas Caiion of Colo. 



2. Rosa pratincola Greene. {R. Arkansana S. Wats. ; also Coult. Man. ; 

 not Pbrter.) On prairies and plains from Minn, and Alb. to Kans. and Colo. 

 — Alt. 4000-6000 ft. — Veta Pass ; Colorado Springs. 



3. Rosa Sayi Schweinitz. On hills and mountains, in. open woods, from 

 Que. and Alb. to Mich, and Colo. — Alt. 5000-10,000 ft. — North Cheyenne 

 Caiion ; Cottonwood Lake ; Ruxton Park, Pike's Peak ; Front Range, Lari- 

 mer Co. ; Blue River, above Kremmling ; Minnehaha ; Hounold ; Boulder ; 

 Columbine ; Marshall Pass ; falls of Poudre ; west of Steamboat Springs ; 

 Campton's ranch; Beaver Creek; Horsetooth Mountain; gulch west of Pen- 

 nock's; Boulder; Eldora to Baltimore. 



4. Rosa Engelmannii S. Wats. In open woods from Upper Mich, and N. D. 

 to Tex. and Colo. — ^Alt. up to 9000 ft. — Manitou ; headwaters of Pass Creek ; 

 Minnehaha Falls. 



5. Rosa Underwoodii Rydb. In carions of Colo. — Alt. 8000-9000 ft. — Box 

 Caiion, west of Ouray; La Plata Canon. 



6. Rosa manca Greene. In the mountains of Colo. — Alt. 7500-9000 ft. — 

 Mancos; southeast of Ouray. 



7. Rosa melina Greene. In the mountains of Colo, and Wyo. — Alt. 6000- 

 10,000 ft. — Chambers' Lake; West Spanish Peak; southeast of Ouray; Cerro 

 Summit ; Black Caiion. 



