186 Fernald—Relationships of some American 
the Tyan-Shan Mountains as represented in the Gray Herba- 
rium and by sheet No. 25,339 in the U.S. National Herbarium, 
such specimens as V. Bailey’s No. 5 from South Dakota, 
Coville and Leiberg’s No. 81 from Nevada, and R. S. William’s 
No. 404 from Montana (sheets Nos. 229,983, 275,933, and 
290,087, U. S. Nat. Herb.); or Macoun’s Devil’s Lake plant, 
awson’s South Kootenai Pass Plant, and Macoun’s Crow 
Nest Pass Plant (Nos. 2,050, 23,623, and 24,368, Herb. Geol. 
Sury. Can.); or Lake and Hull’s No. 790 from Washington, 
Rydberg and Bessey’s No. 3,928 from Montana, Rydberg’s No. 
1,006 from the Black Hills, and A. Nelson’s No. 1,647 from 
Wyoming, we shall be further perplexed in separating the 
American species from the Asian. Similar comparisons of 
American specimens with the figures of B. fruticosa, var. 
cunetfolia (which by Regel was identified with B. microphylla), 
lead to the same result. In view of this evidence and the 
essentially identical descriptions of Nuttall and Bunge, the 
writer is still unable to see in Betula fontinalis, Sargent (Db. 
occidentalis, Nutt., not Hook. B. rhombifolia, Nutt., not 
Tausch) anything but B. microphylla, Bunge, of the moun- 
tains of central Asia. 
$ Nanae. Shrubs: wings of the samaras narrower 
than, or very rarely as broad as the achenes. 
The Dwarf Birches like the Canoe Birches present such 
tendencies to intergradation that it is difficult to draw clear 
specific lines between them. Yet in America three fairly 
marked species or centers of variation can be distinguished. 
These are Betula pumila, L., with the young shoots normally 
pubescent with long soft hairs, and quite glandless, but 1m an 
extreme form with glands or resiniferous atoms mixed with 
the long pubescence; B. glandulosa, Michx., with the young 
shoots glandular or resiniferous, at most puberulent with close 
short hairs; and B. nana, L., a tiny shrub with the young 
shoots puberulent or finely pubescent, but vot glandular. In 
its typical form confined to arctic and alpine regions of Green- 
land, Europe and Asia, B. nana is represented in America by 
Berunta NANA, var. Micnwavxm. 
A very dwarf birch with cinereous-puberulent glandless 
branches and tiny suborbicular or flabelliform leaves has beet 
collected at various points in Newfoundland, Labrador, and the 
Hudson Bay pion, and has been referred to Betula nand, 1+ 
or its var. flabellifolia, Hook. An examination of this material 
: shows that the strobiles are made up of simple oblong scales, 
instead of the deeply three-lobed scales characteristic of 2. 
_-nana and most other species of the genus. 
