OBSERVATIONS ON BETULA IN MINNESOTA WITH 

 SPECIAL REFERENCE TO SOME NATURAL HYBRIDS 



C. O. ROSENDAHL 



In 1904, Britton described a new species of birch from Minne- 

 sota^ naming it Betula Sandhergi in honor of the collector, J. H. 

 Sandberg, who found it growing in "Swamps in Hennepin County." 

 The original description contained no information as to whether the 

 new species was a tree or a shrub, nor did it state anything about 

 the nature and color of the bark, probably because adequate data 

 concerning these facts did not accompany the original collection. 



In the 1907 edition of Britton's Manual, the species was inserted 

 in the appendix and numbered 4a, which referred it to a position in 

 the main text next to Betula nigra. It would appear, therefore, that 

 its nearest affinity was assumed to be with the latter species. There 

 seems to be no other reason for this alignment than that the speci- 

 mens sent out by Sandberg, as indicated by the collection in the Her- 

 barium of the University of Minnesota at least, were labeled Betula 

 nigra, for the new species does not resemble the river birch in any 

 of the determining and essential characters. The distribution was 

 given as "Minnesota and Saskatchewan." 



In 1909 B. T. Butler, in a paper on the Western American 

 Birches,- described B. Sandhergi as a "shrub or shrub-like tree with 

 dark brown bark, not separable into layers," and extended the range 

 of the species to Montana. 



From the time of the original collection in 1890 until the autumn 

 of 1911 the species had apparently been entirely overlooked by col- 

 lectors in Minnesota, for no other birch specimens in the entire Uni- 



^ Britton, N. L., Four New North American Birches, Bidl. Torr. Bot. Club, 21:166. 

 1904. 



2 Butler, Bertram T., The Western North American Birches, Bull. Torr. Bot. Club, 

 36:421-440. 1909. 



