Rydberg: Phytogeographical notes 637 



alkaline meadows, which are quite wet in the spring but dry 

 in the autumn. These are: 



*PuccinelHa airoides *Agropyron Smitliii 



*Spartina gracilis * " vtolle 



*Distichlis sfricta * " dasystachyum 



Elynius simplex (Northern Rockies only) 



A few species may be counted to the meadow flora, but they 

 are found only in sandy places, on creek-banks, etc.. and are lim- 

 ited to the Southern Rockies. These are: 



Muhlenbergia simplex Muhlenbergia Wolfii 



" aristata 



The following meadow species are usually most common among 

 shrubs: 



Eatonia pennsylvanica Savastana odorata 



Panicularia nervata Oryzopsis micrantha 



" pauciflora Elymiis glaucus 



So also the following, which, however, are restricted to one 

 region : 



Southern Rockies Northern Rockies 



Stipa Porteri Melica suhulata 



Panicularia Holmii Panicularia elata 



Festuca fratercula Festuca elatior 



3. Dry Valleys and Bench-lands 



The dry valleys and bench-lands are more common and of 

 greater extent in the Montane Zone than in the Subalpine, and 

 more common in the Northern Rockies than in the Southern. 

 Except in the three parks of Colorado (Northern, Middle and 

 Southern) they are also as a rule smaller in the Southern 

 Rockies. The grasses are composed mainly of two elements, the 

 species common to the Great Plains and those endemic to the 

 mountains. In the drier parts of the valleys there are scarcely 

 any high northern ones running south in the mountains. In the 

 southern portion of the Southern Rockies, there are a few species 



