338 Vniversity of California Publications in Zoology, [^ol. 7 



Plants Ordinarily Occurring in Transition and Found in the Pine 

 Forest Mountains 



(Cool, shaded situations in meadows or along streams, except as noted, 

 from 7500 to 8600 feet altitude) 



Prunus demissa (found on favor- 

 ably exposed slopes at 8000 

 feet) 



Aquilegia truncata 



Eibes cereum (ordinarily occurring 

 elsewhere in upper Transition 

 and above) 



Achillaea millefolium lanulosa 



Aphyllon fascieulatum 



Pentstemon confertus caeruleo-pur- 

 pureus 



Cercocarpus ledifolius (on dry, ex- 

 posed ridges 7000 to 8800 feet) 



Iris missouriensis (in meadows and 

 on dry, open hillsides) 



Amelanchier alnifolia (found on 



favorably exposed slopes at 



8000 feet) 

 Arnica chamissonis 

 Aeonitum columbianum 

 Sisymbrium canescens 

 Hypericum formosum 

 Artemisia tridentata (found from 



4100 to 9400 feet altitude) 

 Ceanothus velutinus (on favorable 



slopes) 

 Veratrum calif ornicum (ordinarily 



occurring elsewhere in upper 



Transition and above) 



Plants Ordinarily Occurring in Canadian or Hudsonian and Found in 

 THE Pine Forest Mountains 



(8000 feet and above) 



Pinus flexilis 



Aquilegia truncata 



Ribes cereum 



Arnica chamissonis 



Iris missouriensis (from 7000 feet 



up) 

 Aeonitum columbianum 

 Sisymbrium canescens 



Allium validum 



Ceanothus velutinus 



Veratrum californicum (in mead- 

 ows 7000 feet in altitude and 

 above) 



DISCUSSION OF LIFE ZONES 



The life zones represented in the region are Upper Sonoran 

 and Transition, with a touch of Boreal (see map, pi. 7). 



The desert proper, comprising in this region the broad flats 

 of the Quinn River Valley and the neighboring deserts, is Upper 

 Sonoran. On favorable slopes tongues of this zone invade the 

 mountains to an altitude of 8000 feet at least, as is indicated by 

 the presence at that elevation of Eeithrodontomys megalofis 

 desert i i\nd J'( roniyscus criiiitus. 



The zone of widest extent in the mountains is the Transition. 

 The most conspicuous element of its flora on exposed Hats and 

 treeless ridges was Artemisia tridentata. The most al)nndant 



