406 Rydberg : Notes on Rosaceae 



mistake. Potentilla decurrens of my monograph, and as under- 

 stood by A. Nelson, loc. cit., or A. diversifolia var. decurrens 

 Th. Wolf, mainly, is not the same as Watson's plant. It is a 

 plant related to P. glaucophyUa and P. Ranunculus, while the 

 original P. dissecta decurrens is related to P. ovina J. M. Macoun 

 In the North American Flora, the former is described under the 

 name P. per dissecta. 



Potentilla Ranunculus Lange, which Dr. W T olf associates with 

 P. ranunculoides H. B. K., is not related to that species but to 

 the one just discussed above and to P. glaucophyUa. It is hard 

 to distinguish it from these species except by the rootstock, which 

 in P. Ranunculus is much branched and creeping and densely 

 covered with scales. This character is found in many arctic 

 plants and is perhaps due to the climatic conditions. P. Ranun- 

 culus has usually broader leaflets than P. glaucophyUa and they 

 are less dissected than in P. perdissecta. 



Potentilla multisecta (S. Wats.) Rydb. is closely related to P. 

 perdissecta. Dr. Wolf reduces it back to a variety of P. dissecta, 

 as it was originally described by S. Watson. This is really a 

 transfer to another species, for P. dissecta of Watson was not the 

 same as P. dissecta Pursh, but was P. diversifolia Lehm. This 

 transfer is made, although Dr. Wolf expressly states that he has 

 not seen P. dissecta Pursh. Professor Nelson, loc. cit., has omitted 

 this species, although it has been collected in Wyoming. 



Subviscosae 

 Very little can be said about this group, as little material has 

 been received since my monograph and few new facts have been 

 brought to light since that time. Through further study of Poten- 

 tilla Wheeled viscid ula, I have come to the conclusion that it 

 deserves specific rank and it is given such in the North American 

 Flora. Dr. Wolf has made no change in the species of this group, 

 as he had seen specimens of only P. Wheeled. As stated before, 

 he includes the whole group in his Ranunculoides. 



Concinnae 

 This group has been a little modified from the treatment in 

 my monograph and a few species have been transferred from other 

 groups. 



