Rydberg: Notes on Rosaceae 357 



It is usually much taller and the leaflets are linear-oblong, 5-8 cm. 

 long and only 1-2 cm. wide, obtuse or rounded at the apex and 

 with lanceolate teeth. It was described as Comarum angusti- 

 foliutn by Rafinesque. In the European form the leaflets are 

 elliptic or oval, mostly acute at both ends, with broad and ovate 

 teeth. This is also the prevailing form in arctic and subarctic 

 America, but the two forms grade in numerous ways into each 

 other, and C. angitstifolium can be regarded scarcely more than a 

 variety. So also C. tomentosum Raf. {Potentilla palastris villosa 

 Lehm.). All grades of pubescence occur from a dense and sub- 

 velutinous one to practically none. 



DUCHESNEA 

 Dr. Wolf included Duchesnea indica (Andrews) Focke in 

 Potentilla and associated it with P. reptans, P. canadensis, etc. 

 With Dr. Wolf's broad view of genera this was very natural, but 

 I can not see how he could keep out Sibbaldia and even Fragaria 

 from his Potentilla. All three have lateral styles, and Sibbaldia 

 is even habitually as close to the typical Potentillae as Duchesnea is. 



FRAGARIA 



It is exceedingly hard to draw specific lines in this genus. It 

 is easy to distinguish F. vesca or F. americana from F. virginiana 

 or F. grandiflora, for in the former two the achenes are wholly 

 superficial, while in the latter two they are set in deep pits in the 

 fleshy receptacle, but such species as F. calif mica and F. mexicana 

 connect the two groups, the achenes being in very shallow- pits. 



A twelve years' study of the genus since the publication of my 

 Monograph of the North American Potentilleae, had not changed 

 my views, and the recognized species remained practically the 

 same in my new revision in the North American Flora, only that 

 three new species were described, two varieties given specific 

 rank, and F. multicipita Fernald and the introduced F. grandiflora 

 Ehrh. added. The treatment in my monograph was not followed 

 either by the authors of the Gray's New Manual or by those of 

 the New Manual of the Central Rocky Mountains; and I scarcely 

 expected that it would. The former admits only two species and 

 two varieties as growing in the northeastern United States, while 



