Arctic Plants: Concluding Remarks 135 b 



As the genera Sieversia, Pleuropogon, and Claytonia seem to have been 

 developed at such distant points and to have produced species so closely related, 

 I cannot see any objection to the supposition that the same species may also 

 arise from more than one single area. 



I have mentioned these few data as a mere suggestion supplemental to the 

 explanation of the singular distribution of some of the arctic plants as demon- 

 strated by Darwin, and so exceedingly well exemplified by Nathorst. 



And So we have in the vegetation of the "Barren Grounds" a picture of 

 the arctic flora, as it is now, with its fascinating little flowers adorning the 

 tundras and possessed by a vitality, for ages unsurpassed, acquired and pre- 

 served throughout one of the greatest revolutions in, the history of the earth, 

 known as the glacial epoch. 



