188 Fernald—felationships of some American 
ward, and locally south to Morris Co., New Jersey, Champaign 
Co.. Onto, Lake Co., InprAna and McHenry Co., [x11Nots, in 
Greenland, northern Europe and Siberia. The leaves vary 
much in outline and in the degree of permanence of the pubes- 
cence ; and the samaras in the breadth of the wings and achenes. 
Narrowly obovate and orbicular leaves are often found upon 
the same shrub, so that species or varieties based upon these 
characters (as B. Grayi, Regel, Bull. Soc. Imp. Nat. Mose. 
Xxxviil, 406, t. 6, figs. 9-13) have little value. 
Betula pumila, var. glandulifera. 
In the Great Lake region, however, and from there north- 
ward and westward, where Betula pumila meets B. glandu- 
losa, it presents a perplexing form. In its long pubescence 
(when well developed) the shrub seems to be B. pumila, but 
mixed with the pubescence and sometimes upon the leaves are 
the characteristic glandular atoms of B. glandulosa. Ordi- 
narily, though, the shrub is readily distinguished from the latter 
species by the longer pubescence of the young shoots. This 
intermediate and transitional form, Betula pumila, var. glan- 
dulifera, Regel in DC. 1. ¢., occurs from western Ontario and 
MicuHigan ila ce SasKATOHEWAN and British CoLuM- 
BrA, south to Ipano and OrxEgon. 
BEeTULA GLANDULOSA. 
“ 
8 
On the eastern mountains (Albert, Katahdin and Washing- 
ton), in Labrador, and in the Altai the shrub passes imper- 
ceptibly to a form with orbicular or reniform leaves, var. 
rotundifolia, Regelt (Betula rotundifolia, Spacht); but on 
* Michx., Fl. Bor.-Am. ii, 180 (1808). + Regel in DC., 1. ¢. 172 (1864). 
oe oe $ Spach, 1. ¢. 194 (1841). 
