ROSA 



135 



2. Upright shrubs; styles free, not protruding 



a. Native species and introduced species which 



have become established; flowers pink; 

 "wild roses" 



( 1 ) Definite infrastipular prickles wanting. 



prickles needle-like 



(a) Flowering branches nearly unarmed; 



leaflets usually seven R. blanda 



(b) Stems densely prickly 



x. Semi-herbaceous ; leaflets usually 9 ; 



flowers in clusters R. arkansana 



y. Bushy; leaflets 3-7; flowers usually 



solitary R. acicularis 



(2) Infrastipular prickles well developed, 



prickles enlarged at the base; leaflets 



7-11, small R. Wood si i 



b. Cultivated species, occasionally persisting in 



the vicinity of old gardens 



(1) Leaflets 1-2 cm. long 



(a) Foliage glandular 



x. Stems green, stout infrastipular 



prickles; flowers pink R. rubiginosa 



y. Stems brown, no infrastipular prick- 

 les; flowers yellow R. foctida 



(b) Foliage glabrous, stems brown, prick- 



les bristle-like ; flowers white, yel- 

 lowish or pinkish R. spinosissima 



(2) Leaflets 2-5 cm. long 



(a) Leaflets downy beneath, not glandular. 



or very slightly so 



x. Twigs red, leaflets thin, flowers pink R. cinnamomea 



y. Twigs grayish brown, leaflets thick, 

 leathery and wrinkled ; flowers red 

 or white R. rugosa 



(b) Leaflets nearly or quite smooth be- 



neath, more or less glandular, thick; 

 and leathery; flowers pink, white or 

 red 

 x. Prickles slender; leaflets obtuse, 



ru g° se R. gallica 



y. Prickles stout, hooked; leaflets usual- 



ty acute R. centi folia 



