DEPARTMENT OF BOTANICAL RESEARCH. 75 



immediate cause of these differences lies in the presence in the former area 

 of a different climax — the Monterey pine (Pinus radiata). The relations of 

 the developmental processes in the two regions may be represented thus: 



"Monterey Bay Monterey Peninsula 



Oalt forest (climax) Pine forest 



Chaparral 



Dune shrubs 



Pioneers 



It is hoped that habitat data gathered during the past four summers will 

 bring to light the more fundamental causes for these divergences. 



Endemic Trees of the Monterey Peninsula, by William S. Cooper. 



(1) Monterey pine (Pinus radiata). — The distribution of the species in the 

 Monterey region was plotted upon a base-map as a first step in an attempt to 

 explain its peculiarities of present range. Much new information was ob- 

 tained with regard to its relations to soil and to other communities, special 

 attention being given to the tension lines between pine and other vegetation 

 types. Eroding sand dunes and excavations in the same afforded excellent 

 opportunities for the study of its root system. A comparative rainfall study 

 of the region has been carried on for three years. The results for the season 

 1919-20 have been reported. In 1920-21 several of the instruments met 

 with disaster. The results for 1921-22 confirm the conclusions tentatively 

 drawn after the season 1919-20: that the Santa Lucia mountain mass is the 

 determining factor in producing local differences in the seasonal total, which 

 were even more striking in the past winter than in 1919-20; and that the 

 distribution of Monterey pine (and also Monterey cypress) bears no direct 

 relation to these differences. 



(2) Monterey cypress (Cupressus macrocarpa). — The distribution of the 

 species was mapped as in the case of the pine, with special reference to the 

 localities and conditions where reproduction is taking place. Along the 

 southern coast of the Monterey Peninsula, where the cypresses grow in a 

 thin line close to the shore, they were found to be invading the pine forest 

 that dominates the peninsula in one limited area; elsewhere they are barely 

 holding their own. Individual trees growing under a variety of conditions 

 were carefully examined, and material was collected for comparative anatomi- 

 cal investigation. Through the courtesy of the Del Monte Properties Com- 

 pany a number of complete trunk-sections were obtained from stumps of 

 some of the largest trees. These revealed striking abnormalities in manner 

 of growth which await detailed study. 



