Rydberg: Phytogeographical notes 



325 



K. HOG-BACKS AND DRY RIDGES 



The flora of the hog backs in the Montane Zone, especially in 

 its upper part, resembles that of the Subalpine Zone; in the lower 

 regions there are many of the species of the dry plains added. Be- 

 sides these there are a few restricted to the Montane Zone; nearly 

 all of these are endemics. The flora consist of the following: 



i. Eastern or transcontinental 

 Juniperus sibirica Bouteloua gracilis 



Carex praticola Koeleria gracilis 



Carex stenophylla Poa crocata 



Calamagrostis purpurascens 



Lewisia rediviva 

 Oreobroma pygmaea 

 Oreobroma nevadensis 

 Draba lutea 



Lesquerella alpina 

 Eriogonum (6 species) f 

 Physaria vikdifera 

 Physaria acutifolia ' 

 Trifolium nanum 

 Trifolium dasyphyllum\ 

 Kentrophyta aculeata 

 Kentrophyta Wolfii\ 

 Aragallus minor 

 Phlox depressa 

 Phlox Kelseyi 



2. Western 



Sedum stenosepalum 

 Petrophytum caespitosum 

 Leptodactylon purgens 



3. Endemic 



Chrysopsis pumila 

 Townsendia strigosa] 

 Townsendia montana\ 

 Erigeron ursinus 

 Antennaria rosidata\ 

 Tetraneuris lanigera\ 

 Tetraneuris brevifolia 

 Senecio Purshianus 

 Senecio Fendleri\ 

 Senecio werneriaefolius] 



SAND HILLS AND SAND-HILL DRAWS 

 While the best developed sand and sand-hill draws are found 

 in the region of the Great Plains east of the Rockies, and in the 

 desert plains of the Great Basin west of the same; they are found 

 also in the Submontane and Montane Zones. In the latter the 

 sand-draws are found mostly in the bottoms of the canyons and the 



