500 Rydberg : Notes on Rosaceae 



NlVEAE 



This group is represented in the North American Flora by nine 

 species. Of these, two are proposed as new, P. nipharga and P. 

 Pedersenii, the first based on specimens referred to P. nivea and 

 several of its varieties, the latter based on P. subquinata Peder- 

 senii Rydb. 



Dr. Simmons in his Flora of Ellesmere Land remarked: 

 "Rather might it be justifiable to distinguish all the arctic forms 

 with deeply incised leaflets, from the typical P. nivea, which has 

 them more rounded and feebler dentate. I have, however, had 

 too little opportunity to study them from nature, to be able to 

 give any definite opinion about it. . . . Rydberg has, however, 

 not only established a new species P. quinquefolia for the plant 

 here in question, but . . . ." If we compare this quotation with 

 the other one from the same discussion given above we notice that 

 Dr. Simmons contradicts himself. In the first quotation he states 

 "there being not the slightest cause to look upon it as a species" 

 and in the latter "rather might it be justifiable to distinguish all' 

 the arctic forms. ..." These arctic forms with deeply incised 

 leaflets, certainly look very different from P. nivea proper, but at 

 the same time they are not the same as my P. quinquefolia. As 

 I could not find any available name for them I proposed P. 

 nipharga in the North American Flora. The plant is not exclu- 

 sively arctic, for similar specimens, although usually smaller, have 

 been collected in the Rockies, especially in Utah. Some of the 

 specimens included in P. nivea dissecta by S. Watson belong here, 

 others belong to P. divisa Rydb. The name dissecta is, however, 

 not available. Potentitta nivea subquinata Lange is probably a 

 form of this with some quinate leaves, but as the name P. sub- 

 quinata has been applied to another species, it is not available 

 for this. It includes probably P. nivea arenosa Lange, but it is not 

 P. nivea arenosa Turcz. I think that it is P. nivea pinnatifida 

 Lange (not that of Lehmann), but pinnatifida can not be used as a 

 specific name for it. It is the same as P. nivea altaica Rydb., at 

 least as far as the Utah specimens are concerned. I thought that 

 it was the same as P. altaica Bunge, but have seen my mistake. 

 I agree fully with the opinion of Dr. Simmons that "it [P. altaica] 

 does not belong to P. nivea, 1 ' not even if P. quinquefolia, P. ni- 



