236 CLIMAX FORMATIONS OF WESTERN NORTH AMERICA. 



Most of this occurs as snow, and results in much more extensive snow-caps 

 and snow-fields than occur in the Rocky Mountains at corresponding latitudes. 

 For the present, the serai relations must be assumed from those in the 

 Petran association (p. 233). This doubtless affords a fairly accurate idea 

 of the processes, since the two associations have so many dominants in common. 



Northern {Catcadea, etc.): 

 Pulsatilla occideDtalis. 

 Lupinus lyallii. 

 Lupin US subalpinus. 

 Lupinus volcanicus. 

 Castilleia oreopola. 

 Castilleia pallida. 

 Potentilla flabellifolia. 

 Valeriana sitchensis. 

 Erigeron salsuginosus. 

 Erigeron radicatus. 

 Erigeron uniflorus. 

 Gentiana calycosa. 



Southern {Sierra Nevada): 

 Trifolium monanthum. 

 Sibbaldia prociunbens. 

 Salix arctica. 

 Lupinus lyallii. 

 Senecio aureus borealis. 

 Mimulus primuloides. 

 Gentiana newberryi. 

 Caatilleia culbertsonii. 



SOCIETIES. 



Artuca parryi. 

 Sieversia turbinata. 

 Silene acaulis. 

 Veronica alpina. 

 Sedum roseum. 

 Polygonum viviparum. 

 Epilobium alpinum. 

 Epilobium hornemannii. 

 Epilobium anagallidifolium. 

 Salix arctica. 

 Salix nivalis. 

 Salix reticulata. 



Pentstemon confertus. 

 Antennaria alpina. 

 Dodecatheon alpiaus. 

 Sedum roseum. 

 Horkelia gordonii. 

 Solidago multiradiata. 

 Agoseris aurantiaca. 

 Thalictrum alpinum. 



Draba aurea. 

 Draba nivalis. 

 Arenaria biflora. 

 Dryas octopetala. 

 Sibbaldia procum^bens. 

 Agoseris aurantiaca. 

 Phacelia sericea. 

 Phlox condensata. 

 Trollius laxus. 

 Erythronium grandiflorum. 

 Ranunculus eschscholtzii. 

 Douglasia nivalis. 



Ranunculus eschscholtzii. 

 Erigeron salsuginosus. 

 Erigeron uniflorus. 

 Gentiana amarella. 

 Cerastium arvense. 

 Antennaria dioeca. 

 Campanula rotuudifoUa 

 alpina. 



