FLORA OF THE SANTA CATALINA MOUNTAINS, 39 



fornia and only one of them has been reported from Colorado. These 

 plants are: 



Quercus oblongifolia. 

 Quercus arizonica. 

 Quercus emoryi, Tex. 

 Vauquelinia calif arnica. 

 Juniperus pachyphlcea, Tex. 



Arctostaphylos pungens, Cal. 

 Garrya wrightii, Tex. 

 Dasylirion wheeleri, Tex. 

 Agave palmeri. 

 Nolina microcarpa. 



Pinus cembroides, Tex. 

 Mimosa biuncifera, Tex. 

 Chrysoma laricifolia, Tex. 

 Eriogonum wrightii, Col., Tex. 



The Encinal likewise comprises a number of plants which reach their 

 maximum occurrence on the Great Plains or else possess areas of dis- 

 tribution which are chiefly to the northeast of Arizona. Among these 

 are Bouteloua obligostachya, Bouteloua hirsuta, Bouteloua curtipendula, 

 Polygala alba, Artemisia ludoviciana, Artemisia dracunculoides, and 

 Stephanomeria runcinata. 



The elements which are common to the flora of California are few, 

 as is true of the Desert, and are almost solely comprised in the follow- 

 ing: Zauschneria calif ornica, Amorpha calif ornica, Bouvardia triphylla, 

 and Brickellia californica, not to add Arctostaphylos pungens, which has 

 its maximum extension southward into Mexico. The Encinal contains 

 a number of forms which have been but recently segregated from well- 

 known species, among them Rhus racemulosa, Rhamnus ursina, and 

 Prunus virens. So little is known of the ranges of these species that 

 it is impossible to state in how far they may represent contributions 

 from distant floras or to what extent they represent forms that have 

 been differentiated in the Arizona-Sonora region. 



The only northern element in the Encinal flora seems to be that 

 which has been mentioned as occurring also in the Great Plains, while 

 the mountainous regions of Colorado and Utah have contributed even 

 fewer species than has the Calif ornian region. 



THE FOREST FLORA. 



The Forest region of the Santa Catalinas possesses strong floristic 

 affinities both with the Mexican cordillera and with the Rocky Moun- 

 tains of Colorado and their southern extension in New Mexico. The 

 majority of the plants which take a conspicuous place in the vegetation 

 of the Forest are members of northern genera. Many of these members 

 are identical with Rocky Mountain species, while many others have 

 their chief range in the mountains of northern Mexico. There are also 

 representatives of a few genera which are distinctively Mexican, a few 

 species of northwestern relationship, and a few apparently of restricted 

 range in the desert mountains of Arizona and New Mexico. 



As examples of the large Rocky Mountain contingent in the Forest 

 flora may be mentioned: 



Abies concolor. 

 Pseudotsuga mucronata. 

 Disporum trachycarpum. 

 Salix scouleriana. 

 Populus tremuloides. 



Acer glabrum. 

 Jamesia americana. 

 Symphoricarpos oreophilus. 

 Eraser a speciosa. 

 Dugaldia hoopesii. 



Erigeron macranthus. 

 Heuchera rubescens. 

 Brickellia grandiflora. 

 Gilia thurberi. 

 Achillea lanulosa. 



