I From the Bulletin op the Torrey Botanical Club, 44: 65-84. 26 F 1917 J 



Notes on Rosaceae — XI 



Per Axel Rydberg 



Roses of California and Nevada 



Two years ago I had practically completed the manuscript for 

 the monograph of the genus Rosa to be printed in the North Amer- 

 ican Flora. As this would only make half a part as usually pub- 

 lished, and as the rest of the manuscript for the same part, which is 

 to be contributed by other persons, is not yet ready and may not be 

 for some time, I thought it would be advisable to publish some of 

 the notes and some of the descriptions of new species in advance. 

 Besides, Professor Le Roy Abrams, of the Leland Stanford Uni- 

 versity, has sent me for determination the collection of North 

 American roses, found in the herbarium of the said institution. 

 I therefore think it is a proper time to put on record my present 

 knowledge of the genus Rosa, with particular reference to California 

 and Nevada, the two states best represented in that collection. 



Key to the groups aiicl species 



Pistils numerous; styles as well as the upper part of the hypan- 

 thium persistent. 

 Flowers corymbose or, when solitary, supported by bracts; 

 achenes borne both on the inner walls and in the 

 bottom of the receptacle; leaflets large. 

 Stem with scattered prickles, rarely also with inter- 

 mixed bristles; sepals distinctly lobed; foliage glan- 

 dular-punctate, sweet-scented. I- Caninae. 

 Stem, at least the young shoots, bristly; prickles infra- 

 stipular or lacking; sepals entire or only the outer 



65 \ 



