28 University of California Publications. [botany 



strata which come to the surface on the moimtain side. Water 

 from ineltiug- snow or from rains on the upper slopes percolates 

 slowly through the soil and between the granitic strata of the 

 mountain, to be released during the summer months at points 

 farther down, the strata thus serving as reservoirs. By the 

 crumpling or spreading of the strata it is often allowed to come 

 to the surface, and wherever this occm-s we find the small hillside 

 bogs or the larger meadows so common on San Jacinto. Some- 

 times these are scarcely more than springs with the accompanying 

 fringe of green, l)ut more often they form conspicuous patches 

 on the hillsides. There is one of these on the west side at about 

 8000 feet altitude that is large enough to be used as a landmark 

 and can be seen for a distance of several miles, while in Tahquitz 

 Valley meadows of this class are sometimes a mile long. The 

 vegetation of the smaller hillside meadows is largely made up of 

 true grasses, Agrostis tenuis and tSporoholus gracillimtis predom- 

 inating, with species of Bromus on the margins. Accompanying 

 these are a number of the higher plants, among the more 

 frequent of which are Sist/rinchium helium, Mimulus primuloides, 

 M. Langsdorfii Tilingi and Rumex salicifolius. 



In the valley meadows the rise of moisture is due to the fact 

 that the strata at the lower end of the valley are so placed that 

 the water can escape only after it has risen to the surface. This 

 may be brought about either by the convergence of those strata 

 forming the valley walls, or the underlying strata of the valley 

 floors may be curved upward at the mouth of the valley, thus 

 assuming a transverse position and blocking the further passage 

 of underground water. The soil is in most cases deep and rich 

 since the valley floors have received the deposits brought in from 

 the surrounding hills, and these meadows contain, besides the 

 grasses, a number of important rushes and sedges, these some- 

 times becoming the dominant elements. 



Of these meadows there are five which contain over one 

 hundred acres. By far the largest and most valuable is the one 

 occupying the middle portion of the Thomas, or Hemet, Valley 

 at an average altitude of 4400 feet, this including about 2000 

 acres, all of which is used as pasturage for cattle. The water 

 sup])ly is derived from a high ridge, an ofl'-shoot from Tahquitz 



