FLORA OF THE YELLOWSTONE NATIONAL PARK. 13 



Bebb, and a form of Salix glauca, L., and the following rather 

 rare and local species : Salix longifolia, Muhl. ; Betula occi- 

 dentalis, Hook; Alnus viridis, D. C.; A. incana, Willd., var. 

 virescens, Wats.; Prunus demissa, Walpers. ; Pyrussambucifolia, 

 Cham, and Schlecht ; Amdanchier alnifolia, Nutt. ; Ceanothus 

 velutinus, Dougl. ; Ehamnus alnifolia, L'Her. 



The timber trees of the region, with the exception of the 

 widespread Populus tremuloides and Juniperus Virginiana, are 

 western species, but several of the shrubs range across the 

 continent. 



The Park has suffered at various times from the ravages of 

 fire. There is probably 100 square miles of burnt forest. Over 

 a large portion of the region will be found masses of fallen 

 timber in the green and standing forest, principally in that of 

 Abies and Picea. 



There are some areas of considerable extent which are not 

 forest covered, and at lower elevations covered with a luxuriant 

 growth of grass and more or less sage-brush. The most exten- 

 sive of these are in the northeast portion, in the vicinity of the 

 Mammoth Hot Springs, about the mouth of the East Fork, and 

 along this stream. 



The former, including the greater portion of the region of Mt. 

 Evarts, Blacktail Deer Creek, Swan Lake and the upper West 

 Gardiner, and generally covered with local drift, has an area of 

 forty square miles, and is the southern extension of the dry 

 timberless region of the valley of the Yellowstone. This with 

 some interruptions extends to the East Fork. The latter 

 comprising the valley of the East Fork to Cache Creek and 

 the slopes on each side ; the northern portion of Specimen 

 Ridge and across the Yellowstone River about Antelope Oreek 

 has an area of fifty square miles, twenty of this belonging to the 

 valley of the East Fork. Besides these are Hayden Valley, 

 eighteen square miles ; Upper and Lower Geyser Basins and East 

 Fire-hole River, fifteen square miles ; Pitchstone Plateau, Madi- 

 son Plateau, and Falls River Basin, forty square miles ; Valley 

 of the Upper Yellowstone, thirty square miles, and tops of the 

 subalpine and alpine plateaus, the slopes of w^iich are densely 

 timbered, along the Upper Yellowstone thirty square miles. 

 Add to these about eighty square miles for all minor areas, 



