

406 THE SYLVA OF MONTANA. 
river, though the climate is so much milder than that of the 
Upper Missouri. This is an additional reason for consider- 
ing the western species (of California, etc.) distinct from 
the eastern, though that of Utah and Western Texas may 
very probably be the latter. The Rhus shows a distribution 
the reverse of this, as compared with the eastern F. glabra. 
SwoorH Marie (Acer glabrum). This commences to 
appear at the eastern base of the Rocky Mountains, and 
grows entirely across to Fort Colville and the east slope 
of the Cascade Range, becoming forty feet high and a foot | 
in diameter. A. tripartitum Nutt., is merely a young or 
dwarfed form of it in dry soil. 
CHOKE-cHERRY (Cerasus Virginiana?).* A tree, appa- 
rently this species, grows all the way across the mountains, 
extending to the Bitterroot Range, and growing thirty feet 
high and six inches in diameter. A small cherry tree, » 
rather a shrub, grows about the borders of the Columbia 
Plain, apparently the same in leaf, but I think the fruit is - 
larger. Ihave never seen the flowers. 
Cuerry (Cerasus mollis?). T found a shrub at the Coeur 
d'Alene Mission and westward, which I took for this from 
the leaves. It is stunted in that latitude. 
Western MouxraiN-asn (Pyrus fraxinifolia? vel Amer- 
tcana?). The Mountain-ash of the western mountains, 
scarcely distinct from that of the north-east, first appeared 
on the east slope of the Coeur d'Aleüe Range, and extends 
in small numbers to Fort Colville, scarcely deserving to be 
called a tree anywhere. I did not find it with fruit on this 
route. 
River Hawrnorn (Crategus rivularis). A hawthorn 
with black berries, and otherwise the same every way, €x- 
tends from the east base of the Rocky Mountains, west to 
the Cascade Range (“Willamette River," Nutt.), forming 2 
_ shrubby tree fifteen to twenty feet high. It is finest along 
the Spokan River. 
* See Torrey and Gray’s Flora of Nebraska. 




