LABORATORY FOR PLANT PHYSIOLOGY. 65 



Strand Vegetation of the Pacific Coast, by William S. Cooper. 



Two weeks during the summer of 1923 were spent in completing field 

 work upon the strand vegetation of the Monterey region. The usual annual 

 counts and measurements of permanent plots, established in 1919, were made. 

 Forty-five photographic records of 1-meter areas were obtained. The 

 rainfall for the preceding wet season was measured at nine stations within a 

 radius of 20 miles from Carmel, the results confirming conclusions drawn from 

 previous studies. With the aid of Mr. Remond Richardson, of the Depart- 

 ment of Geology of Leland Stanford Jr. University, a physiographic survey 

 of the dune region of Monterey Bay was made, the recent history of the 

 coast being worked out and the limits of the dune area determined as accu- 

 rately as possible. 



Bacteria in Arid Soils, hy Laetitia M. Snow. 



The work has been undertaken in order to compare the types of bacteria 

 in arid soils exposed to different climatic conditions. 



The plan is to use soils as nearly as possible similar in physical character- 

 istics, but situated in different parts of the country, such as wind-blown sand 

 from the Atlantic and Pacific coasts, around the Great Lakes, and in the 

 center of the continent. 



A collection of soil samples was made at each of two points in Brewster 

 County, Texas, but as the soils in both regions had a large proportion of 

 clay, the results may not be comparable with those from sandy soil in other 

 regions. 



At Tucson samples were collected from the south bank of Pantano Wash. 

 This soil was of a loose, sandy nature, giving clear evidence of wind action, 

 and had probably not been under water, other than rain, for a sufficient length 

 of time for the micro-flora to become established. 



Samples were taken at depths of 6 inches, 1 foot, and 2 feet, from three 

 different points, placed in Mason jars, and returned to the laboratory. The 

 soil from each depth was thoroughly mixed and plated in various dilutions 

 in nutrose agar. From these plates total counts, and counts of casein diges- 

 ters and nondigesters, were made at the end of 6 and 10 days, and after the 

 last count all colonies showing the slightest difference to the naked eye were 

 fished and streaked on nutrose agar. 



The data are very incomplete and definite results can not be given at this 

 time, but the observations seem to indicate that : 



1. The greatest number of aerobic forms, capable of growing on the medium 

 used, occurred at a depth of 1 foot, the smallest number at 6 inches, while 

 that at 2 feet was intermediate. 



2. At 6 inches and 1 foot the casein digesters were more numerous than 

 the nondigesters, while at 2 feet the reverse is the case. 



3. As far as could be distinguished from the colonies at the time of fishing 

 them, the actinomycetes predominated and increased with the depth, the 

 molds were scarce, while of the colonies apparently bacteria or yeasts the 

 white forms far outnumber all others, followed at some distance by yellow. 

 A few colonies each of red, pink, orange, and brown forms occurred. 



4. Eighty-one transfers were made and stored for future study. 



