have been studied from very early times and by many 

 investigators ; but the very important matter of the rate 

 at which these carbohydrate materials may be produced 

 in crop plants under standardized conditions of atmos- 

 phere and soil has never been determined. And yet 

 knowledge of such data for each of our major crop plants 

 would seem to be a fundamental prerequisite for any 

 really rational system of agriculture. The value of any 

 crop plant as a food producer is practically a question 

 of its capacity to use sunlight in assimilation under any 

 given set of conditions. 



The Adjustment of the Plant to Its Environment 



The importance of a knowledge of the requirements of 

 different trees and other plants as to different qualities 

 of soil and atmosphere, as emphasized above, can be 

 stated in more general terms, namely: the successful 

 culture of plants of whatever kind and for whatever 

 purpose depends upon having at one's command very 

 complete information on the influence of all the various 

 factors of the environment upon the individual plant 

 species and plant community. Most of the knowledge 

 which we possess along these lines has been gained by 

 the accumulation of the results of empirical methods of 

 trial and failure. But science is now beginning to de- 

 velop more exact quantitative methods under the 

 general head of "ecology." Problems of distribution — 

 the reasons why a certain plant grows in one place and 

 not in another — are also ecological. The Garden pos- 

 sesses a great deal of material for fruitful studies on the 

 requirements and the distribution of different species 

 and on the fundamental laws of the ecology of all plants. 

 To utilize this material effectively there are lacking only 

 the needed personnel and the needed laboratory facilities. 



[15] 



