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CARNEGIE INSTITUTION OF WASHINGTON. 



and the physical and chemical composition of the soil have been determined 

 in the various fields. The root development of each of the crops was studied 

 in several stages of growth under different environments. Marked differences 

 in the root habits were found as well as in the crop yield, but the complete 

 results will not be assembled until after another season's work. 



Transplant Areas and Quadrats, by F. E. Clements and J. E. Weaver. 



Studies in experimental vegetation were again carried on during 1922 by 

 means of surface seeding and sowing in trenches and denuded quadrats and 

 by transplanting seedlings as well as blocks of sod. The stations maintained 

 were, as before, from the subclimax prairie at Nebraska City, Nebraska, to 

 true prairie at Lincoln, Nebraska, mixed prairie at Phillipsburg, Kansas, and 

 short-grass plains at Burlington, Colorado. At Lincoln the local stations 

 ranged from xerophytic gravel-knoll, through high prairie, low prairie, and 

 salt flat, to swamp. In addition, plantings were made at Colorado Springs, 

 Colorado, and at timber-line on Pike's Peak, and sods were again transferred 

 from Arizona and California to Lincoln. Furthermore, many species were 

 grown isolated in cultivated plots to determine the optimum growth and 

 permit the measurement of competition in the prairie. The development of 

 the plants both below and above ground has been fully studied, and complete 

 records have been kept of the activities of several hundred plants at the various 

 stations, as well as continuous records of the habitat factors. A number of 

 additional subdominants have been added to the list of those grown during 

 previous years. Approximately 1,300 slides have been made of the leaves of 

 50 or more species grown through the range of climatic and edaphic con- 

 ditions found in the stations, and it is expected that these will throw additional 

 light on the climatic relations of the grasses in particular. 



The results of the experiments of preceding seasons have been tabulated and 

 summarized. During 1920 and 1921 the conditions for plant growth in terms 

 of rainfall, holard, temperature, humidity, and evaporation were most favora- 

 ble at Nebraska City and Lincoln, intermediate at Phillipsburg, and least 

 favorable at Burlington. Germination and growth at the several stations 

 are summarized in the following table: 



Comparison of germination and growth during 1920 and 1921. 



