160 CLIMAX FORMATIONS OF WESTERN NORTH AMERICA. 



SOCIETIES. 



These are poorly developed in the climax portion generally, but they 

 become more and more abundant through the marginal subclimax zone leading 

 to the adjacent formations, particularly the grassland. This is readily 

 explained by the fact that the sagebrush societies are largely drawn from the 

 grassland associations, and hence the two groups are similar to a large degree. 

 The sagebrush likewise contains a number of grasses derived from the various 

 grass associations. These play a role essentially similar to that of societies, 

 though they are properly to be regarded as extra-formational examples of the 

 particular consociation. The societies peculiar to the sagebrush are largely 

 constituted by halophytic species which persist from the subclimax. Pure 

 stands of Artemisia tridentata are to be regarded as the final condition of the 

 climax. They are characteristically dense and closed, and are often prac- 

 tically destitute of other species, except for a few plants of such ruderals as 

 Sisymbrium altissimum, Lepidium perfoliatum, and Bromus tectorum. The 

 latter regularly simulate striking societies over large areas, but they are 

 properly understood as pioneer annuals of a subsere due to fire or grazing, or 

 usually to both. 



Grass Communities appearing 

 as Societies: 

 Agropyrum spicatum. 

 Agropyrum glaucum. 

 Stipa comata. 

 Stipa viridula. 

 Festuca ovina. 

 Elymus condensatus. 

 Koeleria cristata. 

 Bouteloua gracilis. 

 Hilaria jamesii. 

 Aristida purpurea. 

 Elymus sitanion. 

 Eriocoma cuspidata. 



Vernal Societies: 



Anemone patens. 

 Antennaria dioeca. 

 Anemone globosa. 

 Sieversia ciliata. 

 Potentilla arguta. 

 Astragalus flexuosus. 

 Astragalus drummondii. 

 Astragalus crassicarpus. 

 Allium cernuum. 

 Senecio fendleri. 

 Comandra umbellata. 



Vernal Societies — continued. 

 Aragalus speciosus. 

 Aragalus deflexus. 

 Erysimum parviflorum. 

 Krynitzkia virgata. 

 Heuchera parvifolia. 



Estival Societies: 



Balsamorhiza sagittata. 

 Balsamorhiza deltoidea. 

 Castilleia miniata. 

 Achillea millefolium. 

 Cordylanthus wrightii. 

 Linum perenne. 

 Opuntia polyacantha. 

 Opuntia mesacantha. 

 Eriogonum umbellatum. 

 Calochortus gunnisonii. 

 Allium cernuum. 

 Potentilla pennsylvanica. 

 Potentilla hippiana. 

 Potentilla gracilis. 

 Galium boreale. 

 Erigeron canus. 

 Erigeron pumilus. 

 Eriogonum racemosum. 

 Pentstemon confertus. 



Estival Societies — continued. 

 Pentstemon unilateralis. 

 Pentstemon sti ictus. 

 Geranium caespitosum. 

 Delphinium scopulorum. 

 Lupinus argenteus. 

 Malvastrum coccineum. 

 Campanula rotundifolia. 

 Campanula parryi. 

 Gaura coccinea. 

 Aster bigelovii. 

 Artemisia canadensis. 

 Actinella floribunda. 

 Orthocarpus purpureus albus. 

 Stanleya pinnata. 



Serotinal Societies: 

 Artemisia frigida. 

 Grindelia squarrosa. 

 Carduus undulatus. 

 Carduus plattensis. 

 Wyethia amplexicaulis. 

 Wyethia arizonica. 

 Wyethia helianthoides. 

 Wyethia scabra. 

 Chaenactis douglasii. 



THE COASTAL SAGEBRUSH. 



SALVIA-ARTEMISIA ASSOCIATION. 



Range. — The association is limited to the region from northern Lower 

 California to San Francisco Bay, and from southwestern Nevada to the 

 Pacific Coast. It is characteristic of the lower foothills, between the Stipa 

 grassland or the Larrea desert, and the Adenostoma consociation of the 

 chaparral. It occurs with the latter so much in southern California that 

 it has been regarded as a particular southern type of chaparral, but it now 

 seems that this view can, no longer be maintained. The first recognition 



