178 Fernald—Relationships of some American 
Betula alba, var. minor. 
The dwarf alpine shrub which was described by Tuckerman 
as Betula papyracea, var. minor,* is represented in the Gray 
Herbarium by material from Tuckerman himself. It is not, 
erhaps, the commonest dwarf Canoe Birch of the White 
fountains, but is a form with the small elliptic- or truncate- 
ovate leaves strongly glutinous and quite without pubescence. 
From the comparatively narrow wings of the samaras in Tuck- 
erman’s specimens, Regel took the plant to be a form of 
B. davurvea, Pallas, of eastern Asia, and upon the Tuckerman 
sheet he based his B. duvurica, B, americana.t The shrub 
is, however, more properly a phase of 2B. a/ba, and it occurs 
likewise on the North Summit of Mt. Katahdin, where it 
sometimes has the leaves smaller firmer and more glutinous 
than on Mt. Washington; in Gaspé and in Labrador; and in 
the mountains of Saskatchewan, Assiniboia and Alberta, where 
it intergrades with B. microphylla. Though ordinarily dis- 
tinguished from B. alba, var. cordifolia, by its elliptic- or 
truneate-ovate glabrous leaves, smaller erect  strobiles, and 
smaller samaras, this second dwarf Canoe Birch shows ten- 
dencies to integrade with that form. In its most characteristic 
development this shrub of the New England mountains 
matches B. tortuosa, Ledebour,t described from the Altai Mts. 
of central Asia, where it had likewise been mistaken by Lede- 
our for B. davurica of Pallas. The range of Betula tortuos¢ 
as since been extended through northern Russia to Silesia, 
Finland, Lapland and Greenland, where it is sometimes treated 
as aspecies, but by Koehne and by Guerke as a form of 
alba (B. pubescens, var. tortuosa (Ledeb.) Koehne).$ 
If we compare specimens collected by the late Edwin Faxon 
at “ Willis’s Seat” on Mt. Washington, New Hampshire, and 
sen vinge’s No. 160 from Greenland, distributed from the ac 
ical Museum of Copenhagen as B. odorata, var. tortuosd aD 
* Tuck., this Journal, xlv, 31 (1843). Regel in DO., 1. c., 175 (1864). 
$ Fl. Ross, iii. 652 (1849), ' ene Deutsche Dendr. 109 (1893). 
