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1894.] Botany. 1035 
and soft limestone and sandstone rocks, and in the driest season never 
seems to lack moisture. It belongs to the foothills of the Rocky 
Mountains, but extends eastward as far as the west line of Holt 
County in the Niobrara Canon. The coincidence, at this point, of the 
Black Walnut (Juglans nigra L.) with the Bull Pine is remarkable. 
In the cañon at Long Pine are many flourishing specimens, young and 
old, one with the diameter of three feet. The young ones prove that it 
sometimes fruits, in spite of the late spring frosts. Its western limit is 
nearly coincident with Brown County and the 100th meridian. 
A large block of Black Walnut was found in Cherry County five 
years ago, not far from Fort Niobrara, and was preserved by Surgeon 
Wilcox, showing that it once extended further west. This region 
furnishes but one oak ( Quereus macrocarpa Michx.), which grows to a 
large size. It takes the moist and the dry portions of the cafions 
about equally, where the soil is at all loamy, leaving the most barren 
parts to the Pine. Its western limit is about the mouth of Snake Creek, 
Cherry County, about ten miles west of Valentine. 
A rare and notable tree is the Canoe Birch (Betula papyrifera 
Marsh), which flourishes only where a dark and sheltered spot is 
ished by a steep declivity with a northern exposure. At Fort Nio- 
brara, where these conditions occur in their perfection, surrounded by 
rare plants such as Lonicera hirsuta, Cireaea lutetiana, Osmorrhiza 
claytoni, Carex eburnea, the two latter not having been found else- 
where in Nebraska. You may see noble specimens of this Birch thirty 
inches in diameter. It is reported sixty miles west and further east on 
the Niobrara. : 
The region affords no more useful and hardy tree than the Ash, of 
which we have two species:—the common species from Antelope 
County west to Brown is Fraxinus lanceolata Borck., from Brown id 
west to the Hills, Fraxinus pennsylvanica Marsh. Itisnot al 
distinguish them, as Gray gives a pubescent form of the Green Ash. It 
oceupies the same soil as the Oak, running from the water's edge over 
the cafion line upon the prairie, where it has been fortunate enough 
to escape destruction from fire. We have no tree more capable of en- 
during the rigors of drouth, heat and cold. It seldom attains a size of 
over thirty inches in diameter. 
The Basswood (Tilia americana L.) is found along the Niobrara in 
Brown County, and probably further east; apparently reaching its 
western limit in Cherry County, about four miles west of Valentine. 
It affects the borders of streams. 
