76 S. B. PARISH 



tane region. In addition there is much Arlemesia tridentala, 

 which is not common. But in San Felipe desert conditions 

 prevail, manifesting themselves in the presence of Larreas, Fou- 

 quieras and Agaves. The species of the last named genus is A. 

 deserti Wats, which extends in a broad belt from the base of San 

 Jacinto mountain to the borders of Lower California, where it 

 connects with A. Palmeri Wats. Trelease has proposed a 

 second species, A. consociala, 1 for a part of the plants of this 

 belt, founding it on specimens collected at San Felipe, but the 

 characters relied upon were not recognizable in the field. 



LA PUERTA DE SAN FELIPE 



At the lower end of San Felipe a narrow gorge affords a bare 

 passage for vehicles through a rocky ridge. Formerly it bore 

 the appropriate Spanish name which indicated that it was 

 the portal of entrance to the valley, but now it is more prosai- 

 cally known as "Box Canyon." On its rocky sides grow Juni- 

 perus calif ornica and specimens of Opuntia echinocarpa, 0. chlorot- 

 ica, Cereus Engelmanni, Echinocactus cylindraceus and Mamil- 

 laria phellosperma. Other shrubs were Lycium Cooperi, Con- 

 dalia Parryi and Prunus eriogyna. In narrow seams Arabis 

 perennans and tufts of Cheilanthes Fendleri and Chamcesyce poly- 

 carpa hirsuta found root. Desert conditions are unfavorable to 

 the growth of lichens, and where these prevail lichens are seldom 

 present, so that it was interesting to find a number of crustaceous 

 species in abundance on the more sheltered rock surfaces. 2 



LA PUERTA VALLEY 



The pass opens upon a small valley, whose gentle slope is 

 abundantly grown over with Agave, intermingled with Yucca 

 Mohavensis, Larrea and other shrubs. On the nearer side for- 

 bidding and arid mountains of low altitude divide it from Salton 



1 Rept. Mo. Bot. Card, xxii, p. 53, 1912. 



2 The following species were collected: Acarospora squamulosa (Schrad.) Th. 

 Fr., A. xanlhophana (Nyl.) Fink, Buellia myriocarpa (Lam. & DC.) Mudd, 

 Dermatocarpon hepalicum (Ach.) Th. Fr., Gyrophora grisea Borr. & Turn., 

 Parmelia conspersa (Ehrh.) Ach. and its var. isidiala Neil. 



