McKpnney, Notes on Plant Distribution in Southern California. 167 



occupy the eastern half of the County; wliile tlie western boundarj 

 is marked by the Pacific Ocean. Running along the coast line 

 and parallel with it is a chain of hills, the Laguna Mts. Stretching 

 between the eastern and western chains is a slightly elevated and 

 comparatively level piain, commonly called a Mesa. In many 

 cases the Laguna Mts. run down into the sea.M' Accordingly, flat 

 Sandy beach is not extensive. ^ 



1 

 f 



The year in southern California is divisable into two seasons, 

 the Wet and the Dry. The Dry season lasts approximately from 

 the middle of Mareh to the middle of October. Conversely the Wet 

 seasoii comes between October and March. As will be seen trora the 

 accompanying table, the rainfall even in the Wet season is quite smal 

 in amount. In the season of '99 — '00 I only recall two days during 

 which it rained continuously the entire day. In the absence of exact 

 continuous records for the county, I give the records of the U. S. 

 Meteorological Bureau for City of Los Angeles in the neighboring 

 county. From a climatic point the two counties are quite similar. 



City of Los Angeles, 

 Latitude 34" 3' N. 



County of Los Angeles, California 



Longtitude 118" 15' W. Eievation 103.022 Meters. 



T denotes trace. Precipitation expressed in Centimetevs. 



Corresponding with the small rainfall is the scarcity of btreams 

 of any size. Four streams with a general south-westerly trend run 

 from the Santa Ana Mts.: Santa Ana River, Santiago, Aliso and 

 Trabuco creeks. With the exception of the Santiago Creek which 

 empties inlo the Santa Ana River, all these empty iuto the sea. 

 These streams have but few tributaries, and these, are only found 

 near the heads of main streams. 



The temperature is even and warm through out the year as 

 will be indicated by tables of temperatures of cities to the north 

 and south of the county. 



City of Los Angeles, County of Los Angeles, California. 



Latitude 34" 3' N. Longtitude 118" 15' W. Eievation 103.022 Meters. 



