34 THE BROAD-SCLEROPHYLL VEGETATION OF CALIFORNIA. 



which crossed all slopes and vegetation types, giving two or more 

 examples of each. A trail was cut through the brush connecting 

 these with each other and with a nearby road. The distance between 

 the extreme stations was approximately 800 meters. 



Stations 7 and 8 represent the forest and the remaining eight the 

 chaparral. Of the latter, stations 1, 4, 5, 9, upon south-facing slopes, 

 and 2 and 10, on nearly level summits, were in areas of Adenostoma 

 dominance, and stations 3 and 6, upon north-facing slopes, in Arc- 

 tostaphylos dominance. Quadrats were charted in six of these. 

 A number of statistical quadrats confirm the results. 



Station 1. 



This has the poorest vegetation of any. A quadrat 5 meters 

 square is represented in figure 2. 1 The species within it are given 

 below in order of abundance, with the number of plants of each 

 and the number of individual stems. Exact statistical study of 

 chaparral vegetation is difficult, because of the common habit of 

 growing in clumps and the frequent impossibility of readily deter- 

 mining the limits of a single group. The figures given are therefore 

 not absolutely accurate. 



Clumps. Stems. 



Adenostoma fasciculatum 81 219 



Arctostaphylos tomentosa 9 60 



Total 90 279 



Heteromeles arbutifolia is occasional nearby. The bushes are all 

 small, ranging from 3 to 12 dm. in height, most of them nearer the 

 former figure. In spite of the large number of individual plants, 

 the ground is poorly controlled, large areas being entirely unshaded. 

 Herbaceous growth is practically absent, the quadrat showing not a 

 single plant at the time when it was plotted (August 25). There is 

 no humus superficially visible, and very scanty litter. 



Station 2. 



This station is on the highest point of Jasper Ridge and there- 

 fore most thoroughly exposed to atmospheric agencies. Moreover, 

 with station 1, it differs in soil character from the other eight, as 

 will be later shown. The vegetation is of better appearance than 

 that of station 1, but is still low and scattered, so that it is possible to 

 walk between the bushes in many places. No chart quadrat was 



1 The symbols used in this and the following quadrats are given here. Exponents, except 

 in figure 6, indicate number of stems in a clump. 



A. Adenostoma fasciculatum. B. Baccharis pilularis. Qa. Quercus agrifolia. 



Ab. Arbutus menziesii. C. Ceanothus sorediatus. Qd. Quercus durata. 



Ae. ^Esculus californica. D. Diplacus glutinosus. Qw. Quercus wislizeni. 



Ar. Arctostaphylos tomentosa. H. Heteromeles arbutifolia. R. Rhus diversiloba. 



As. Aster radulinus. Ho. Holodiscus discolor. 



