Vol. n HaU. — Botanical Survey of San Jacinto Moimiain. 41 



a white trail of bare granite in theii* rear. As the ah'eady too 

 scant soil was carried completely away these areas were never 

 reforested and remain as scars on the mountain side. 



Somewhat similar are a few denuded slopes in the chaparral 

 belt. In sjiring'time the streams of the foot-hill caiions, swollen 

 by water from the melting* snow of the higher regions, undermine 

 their banks and thus cause land slides on the steeper hills. The 

 vegetation is carried down into the canons, leaving only ragged 

 areas of bare soil or rock where before were solid thickets of 

 chaparral. Several such denuded areas are shown in the back- 

 ground of plate iii. 



WATER COURSES. 



As compared with those of more northern latitudes the 

 streams of San Jacinto carry but a small volume of water, and 

 yet, since they are found on all parts of the mountain, their in- 

 fluence on the distribution of plants is one worthy of considera- 

 tion among the other factors. They all have their rise at 

 considerable altitudes, the source of some being the numerous 

 small springs, which open on the mountain sides, while others 

 are fed from the banks of melting snow; but all the larger 

 streams, with the exception of Snow Creek, receive their water 

 from the half -boggy meadows of the higher valleys. The smaller 

 streams soon unite to form about six fan-- sized creeks aud these, 

 following the tortuous canons which they have cut into the 

 mountain side, either find their wav to the main San Jacinto 

 River and thence to the sea, or else, by turning easterly, flow out 

 on the Colorado Desert, in the sands of which they are soon 

 lost to view. 



Among the effects produced upon the vegetation by the 

 presence of these brooks the most obvious is that due to the 

 increase of soil moisture along the banks. In rapidly flowing- 

 streams, such as we here have, this influence is not felt for any 

 great distance from the stream, but it is sutflcieut to gather 

 along the watercourses a characteristic riparian formation, quite 

 distinct from the forest formation of the drier slopes. 



As affecting the position of the floral belts their influence is 

 quite marked, the water having a cooling effect on the tempera- 

 B0T.-4. 



