VEGETATION OF THE SANTA CATALINA MOUNTAINS. 27 



arroyos are Rhus trilobata, Baccharis emoryi, Erythrina flabelliformis, 

 Bouvardia triphylla, Amorpha calif ornica, Fendlera rupicola, Morus 

 celtidifolia, and the climber Vitis arizonica. 



On the flood-plains of the larger canons in the Lower Encinal may- 

 be found the lowest examples of several species which become common 

 in the forested region of the mountain, and these are indeed the lowest 

 members of the forest flora, if aquatics are excepted. At 4,900 feet 

 Ceanothus fendleri and Prunus virens are both to be found, growing 

 not only on a flood-plain but in the shade of evergreen oaks. Berberis 

 wilcoxii is found at 5,200 feet growing in shade near a constant spring, 

 and Rhamnus ursina is infrequent at 5,000 feet near streamways. 



During the mid-summer there is an abundant stand of herbaceous 

 perennials and ephemerals on the flood-plains of the Lower Encinal, 

 giving them a much closer carpet of vegetation than is to be found on 

 the adjacent slopes. Abundant and characteristic among them are: 



Artemisia sp. 

 Asclepias tuber osa. 

 Brickellia calijornica. 

 Castilleja Integra. 

 ChamcBcrista leptadenia. 

 Comandra pallida. 

 Cordylanthus wrighiii. 

 Crolalaria lupulina. 

 Diodia teres. 

 Eriocarpum gracile. 



Euphorbia crenulata. 



Gyynnolomia multiflora. 



Hymenothrix wrightii. 



Malvastrum sp. 



Monarda pectinata. 



Solanum douglasii. 



Solidago sparsiflora var. subcinerea. 



Sporobolus confusus. 



Stachys coccinea. 



Stenophyllus capillaris. 



THE UPPER ENCINAL. 



During the ascent from 5,000 to 6,000 feet the most notable change 

 in the vegetation is the gradual increase in the density of the stand of 

 evergreen trees and shrubs (see plates 18, 19, and 20), a change which 

 forms the chief distinction of the Upper Encinal from the Lower 

 Encinal. Quercus emoryi and Quercus arizonica are still the dominant 

 trees, while Pinus cembroides and Juniperus pachyphlcea are somewhat 

 less common. Arctostaphylos pungens and Garrya wrightii are the most 

 common of the larger shrubs and Mimosa biuncifera of the smaller ones. 

 Dasylirion wheeleri, Nolina microcarpa, and Agave palmeri remain 

 abundant, at least on southern slopes, up to 6,000 feet and Agave 

 schottii remains common up to its upper limit at that elevation. With 

 the increasing abundance of the oaks, however, these semi-desert 

 species as well as the cacti become infrequent and are confined to the 

 summits of ridges and the crevices of rocks. 



On steep north slopes, between 5,300 and 6,000 feet, many almost 

 pure stands of Pinus cembroides are to be found and also the lowest 

 individuals of Quercus reticulata, here a low-branched tree of 20 feet 

 in height. Pinus chihuahuana first appears at about 5,900 feet on 

 south slopes, being the only one of the trees which is not found at 

 much lower elevations on north slopes than on south ones — indeed it 

 is not common on north slopes at any elevation. 



