Rhodora 
JOURNAL OF 
THE NEW ENGLAND BOTANICAL CLUB 
Vol. 21. March, 1919. No. 243. 
CONTRIBUTIONS FROM THE GRAY HERBARIUM OF HARVARD 
UNIVERSITY. — NEW SERIES, NO. LVIII. 
LITHOLOGICAL FACTORS LIMITING THE RANGES OF 
PINUS BANKSIANA AND THUJA OCCIDENTALIS. 
M. L. FERNALD. 
IN the Botanical Gazeite for December, 1918, Professor A. H. 
Hutchinson! discusses at length the factors which limit the northern 
ranges of various species of forest trees and presents maps and charts 
which at first glance may appear authoritative. When, however, 
one sufficiently examines the details to see that on the first map Abies 
canadensis (no. 9) is indicated as having a northern limit in Newfound- 
land, central Labrador and southern Keewatin, while Picea canadensis 
(no. 2) extends to northern Labrador, Ungava Bay, and the north- 
west side of Hudson Bay, he at once sees that this paper belongs in 
the same class as many other so-called phytogeographic and ecological 
articles which appear in our American journals. Abies canadensis 
and Picea canadensis are identical! The White Spruce was called 
by Miller (1768) Abies canadensis and by Link (1841) Picea alba, 
but on account of the earlier specific name of Miller's is now known 
as Picea canadensis. In 1803, to be sure, the name Abies canadensis 
was used by Michaux for the Hemlock, which since 1855 has been 
separated as a member of the genus Tsuga, but Hutchinson gives 
Tsuga canadensis a separate range, to the south of Abies canadensis. 
If he is using the name Abies canadensis in a novel sense it is unfortu- 
1 Hutchinson, Bot. Gaz. lxvi. 465—493 (1918). 
