490 Rydberg: Notes on Rosaceae 



Graciles 



The following species were described as new in the North 

 American Flora: Potentilla intermittens, P. alaskana, P. dichroa, 

 and P. camporum. 



As stated in the North American Flora, Potentilla intermittens 

 may be a hybrid between P. glaucophylla and P. filipes, so inter- 

 mediate is it in every respect that a mere glance would suggest 

 its hybrid origin. As I had no direct evidence, however, I pro- 

 posed a specific name and described it, hoping that botanists might 

 study it further in the field. The following specimens belong here : 



Colorado: Cameron Pass, 1896, Baker 25; Buffalo Pass, 1898, 

 Shear 3863. 



Alberta: Foothills, 1897, Macoun 16722. 



Potentilla alaskana resembles P. viridescens in habit but the 

 flowers are much larger, the petals being 9-14 mm. long, the 

 bractlets linear instead of lanceolate, and the leaves densely tomen- 

 tose beneath. It differs from P. gracilis in the lower stem and 

 the appressed pubescence on stems and petioles. Several speci- 

 mens have been seen, but all were from the Island of Kadiak, 

 Alaska. 



Potentilla dichroa is related to P. glomerata but differs in the 

 dense white tomentum of the lower surface of the leaves. It 

 differs from P. gracilis in the thicker leaves, and in the stouter 

 and lower, more leafy stem, which is appressed-hairy. The fol- 

 lowing specimens belong here : 



Montana: Old Sentinel, 1901, MacDougal 185. 



Oregon: Burns, 1901, Griffiths & Morris 766. 



The following I have referred here, although they are less 

 typical specimens: 



Utah: Hot Pots, Wahsatch County, 1905, Garrett F727. 



Nevada: Washoe Valley, Stretch 74. 



Potentilla camporum is somewhat intermediate between P. 

 gracilis and P. filipes, having the toothing of the leaves of the 

 former and the small flowers of the latter. It has much broader, 

 thicker, and more pubescent leaves than the former, more coarsely 

 toothed and more hairy leaves than the latter. The following 

 specimens are referred here: 



South Dakota: Black Hills, Miss Pratt 93 



