and Old World Birches. 187 



This dwarf shrub of ]N[ewfoundland and Labrador is with- 

 out question Betida Michauxii^ Spach,"^ based upon the B. 

 nana of Michaux, not L., and made by Spach the type of his 

 section Apterocaryon. Subsequently the plant was raised to 

 generic rank by Opiz,f and called Apterocaryon Michauxii ; 

 while, on the other hand, Kegel in his first Monograph treated:j: 

 the plant as a variety of B. nana^ though he later recognized§ 

 it as distinct. Habitally the plant is quite inseparable from 

 the European j5. nana ; and since sheet N"o. 334,54:0 of the 

 United States National Herbarium, from l^ugsuak Peninsula 

 in Greenland, shows strobiles with simple and variously divided 

 scales, it seems that Kegel's earlier treatment of the plant was 

 wiser and that the Newfoundland and Labrador representative 

 of Betula nana is var. Michauxii (Spach) Kegel. 



Betula pumila. 



In its normal form Betula pumila, JL.\ has the leaves and 

 branchlets quite glandless and in their youngest stages densely 

 pubescent with silky hairs. The shrub, however, passes imper- 

 ceptibly into a state (var. glahrescens, Kegel) in which the 

 branchlets and leaves are quite glabrous. This tendency is 

 common, but apparently not of such constancy as to merit 

 special recognition. It is interesting to find, however, that the 

 specimens which represent this tendency are inseparable from 

 B. aljoestris, Fries,^ of Greenland, Iceland, Scandinavia and 

 north Germany, an identity which was at least suspected by 

 Kegel."^^ Such specimens in the Herbarium of the Geological 

 Survey of Canada as Macoun's No. 23,840 from Anticosti and 

 Waghorne's No. 23,821^ from Labrador are quite inseparable 

 from sheet No. 149,806 in the U. S. Nat. Herb, of B. alpestris 

 from the Dovre Mts., Norway {AhTberg) and a sheet in the 

 Gray Herbarium from Lapland {Anderssori), except in the 

 length of the petiole. This character, however, is very incon- 

 stant and it seems to the writer an insnfiicient point on which 

 to keep apart two plants which are otherwise inseparable. 

 Nor are the extreme American plants otherwise different from 

 the plate representing B.fritticosa, var. hiimilis, Keichenbach 

 (Ic. Fl. Germ, xii, fig. 1280) and referred by Guerke to B. 

 alpestris, and the plate of B. alpestris in Flora Danica (Suppl. 

 t. 37). The name B. pumila, however, long antedates B. 

 alpestris, Fries, and it should now be apj)lied to the shrub of 

 northern Europe as well as America. The true Betula pumila 

 occurs in swamps from Labkadoe and Newfoundland west- 



* Ann. Sc. Nat., ser. 2, xv, 195. f Lotos, v (1855), 258. 



X Regel, Mon. Bet. (1861) 45. 



§ Regel in DC. Prodr. xvi, part 2 (1864), 171. || Mant. 124 (1767). 



^ Summ. Veg. Scand. i, 212 (1846). ** Regel in DC, 1. c. 173. 



