180 Rydberg : Further Studies on the Potentilleae 



Kuanersuit on Disco, 2770 ; Engelskmandens Havn, Disco, iSjc) 

 (a slender depauperate form*). 



Potentilla emarginata Pursh, Fl. Am. Sept. 353. 18 14 



Undeveloped or depauperate specimens of this species resemble 

 often very closely P. nana and I am now inclined to regard the 

 two species as forms of one. In Alaska and other arctic regions 

 of the American Continent they seem distinct enough but the plants 

 from Greenland, Spitzbergen and Novaja Semlja are often so con- 

 fusing that it is hard to tell to which to refer them. 



The specimens collected by Mr. Pedersen are as follows, those 

 approaching P. nana are marked by (?). 



Greenland: Skarvefjord, 1898, Pedersen, 2jg ; Ingigsok, 

 2i8a^.nA 2i8b ; Mudderbugten, <)66 (?) ; Ekalunguit Itivnerit, 

 1414. ; Plateau behind Ujaragsugsak, 3ogg ; all on Disco. 



Potentilla nana Willd.; Schlecht. Mag. Ges. Naturf. Fr. Berlin. 



7 : 296. 181 3 



Among the many species of P. emarginata sent from Copen- 

 hagen, there are two sheets, however, that represent the typical P. 

 nana with its round teeth and rounded obtuse sepals and bractlets, 

 viz.: 



Greenland: Manatsook, 1883, Dr. Berlin; Upernaviarsur, 

 1887, Ryder, 7.^ 



Potentilla nivea L. Sp. PI. 499. 1753 



Of the typical P. nivea the collection sent contains many sheets, 

 the following was the only one collected by Mr. Pedersen : 



Greenland: Rocks behind Kuanersuit on Disco, 1898, J/! 

 Pedersen, 2J06. 



*0n the label is written ^^ Potentilla f?iaculata Pourr. var. debilis Lehm. in var. 

 hirtumV.gQ. transiens." Lehmann cites under the var. debilis, P. incisa Desf. as a 

 synonym. The latter is figured in Nestler's Monograph as a large plant with nar- 

 rowly cuneate leaflets deeply incised at the apex, and quite unlike the specimens cited 

 above. The latter I cannot distinguish from the typical P. Langeana except in size. 



I The last was determined by Lange as P. tiivea prostrala, which must be a mis- 

 take as it is unlike the other specimen collected by Vahl and does not agree with the 

 description. 



