238 BOTANICAL GAZETTE [APRIL 
catkins about 14% in. long and ¥% in. thick, with scales longer 
than broad, the middle lobe being acuminate and much elon- 
gated. Specimens of this tree, which is perhaps the largest 
of all birch-trees, were first gathered on the shores of the straits 
of Fuca by Dr. John Scouler during his visit to the northwest 
coast in 1825-1827. These specimens were described by Hooker 
in his Flora Boreali-Americana as Betula occidentalis, although 
with them he united a specimen collected by Douglas in the 
interior but west of the Rocky mountains. The tree from the 
straits of Fuca appeared first in the description of Betula occiden- 
talis which was evidently drawn principally from the specimen 
of that tree, and must be considered the type of Hooker’s 
species, while the second specimen included in this description, _ 
collected by Douglas, is the Rocky mountain form of Betula 
papyrifera. In the shape of the leaves this species resembles 
some of the forms of Betula papyrifera. The bark, however, is 
very different from that of the eastern tree, and it is probably 
best to consider it a species. 
Third, the half-shrubby dark-barked species with spreading 
gracefully drooping stems which ranges as far south as Colo- 
rado, Utah, and northern California. This plant was collected 
by Nuttall on the Sweetwater, one of the branches of the Platte, 
and was first described and figured by him as Betula occidentalis 
(Sylva 1: 23. pl. 7). Torrey in the Botany of Fremont’s Expe- 
dition repeats this error. This same species was also described 
and figured in King’s Rep. (5 : 323. pl. 35) as Betula occidentalis 
by Watson who repeated his error in the Botany of California, and 
it is this plant which is described and figured as Betula occiden- 
fais in my ninth volume of The Silva of North America, where 
an allusion only is made to the true Betula occidentalis of the 
coast in a note under Betula papyrifera. Nuttall found another 
small birch in the Rocky mountain region and on the plains of 
the Columbia which he described and figured as Betula rhombi- 
folia in the first volume of his Sylva published in 1842. This | 
plant, judging by one of Nuttall’s original specimens in the Gray 
Herbarium, is the narrow-coned form of the plant described by 

