The Origin of the Desert Climax and Climate 



93 



Oryzopsis hymenoides 

 Poa nevadensis 

 Elymus sitanion 



Aristida purpurea 

 Aristida p-wrighti 

 Aristida divaricata 

 Aristida d-parishi 

 Aristida californica 

 Aristida glauca 



Mixed prairie 



Hilaria jamesi 

 Bouteloua gracilis 

 Bouteloua racemosa 



Desert plains 



Hilaria rigida 



Triodia pulchella 



Sporobolus cryptandrus flexuosus 



Sporobolus wrighti 



Muhlenbergia porteri 



Muhlenbergia iemmoni 



California prairie 



Poa scabrella 



Stipa speciosa 

 Stipa pulchra 



Coastal prairie 



Andropogon saccharoides Andropogon glomeratus 



Serai dominants 



Distichlis spicata Hordeum jubatum 



Sporobolus airoides Phragmites communis 



Sporobolus asperifolius Imperata hookeri 



Few of these constitute extensive communities today. Hilaria 

 rigida and Triodia pulchella are the most important in this re- 

 spect, and next in order are Oryzopsis hymenoides, Aristida 

 p-turighti, Stipa speciosa, Poa scabrella, and Distichlis spicata. 

 The most complete community relicts so far discovered occur in 

 the Avawatz Mountains on the south rim of Death Valley at an 

 altitude of 4300 feet. Here are associated Hilaria jamesi, H. 

 rigida, Aristida p-wrighti, Stipa speciosa, Poa scabrella, Oryzop- 

 sis hymenoides, and Sporobolus c-flexuosus, at their best on 

 rocky north exposures. In sandy plains about the playas in the 



