37<) 



THE AMERICAN NATURALIST [Vol. XLIII 



least accurate, not those which are the most easily suscep- 

 tible of improvement. It is, indeed, often a waste of 

 energy to seek the highest possible accuracy in all of a 

 series of measurements where one or more are at best of 

 low accuracy. The accuracy of the resulting summation 

 must be subject roughly to the error of the least accurate 

 of the members. 



It is not my purpose to submit any recommendations 

 as to improvement in the general philosophy of ecology, 

 although we must all realize that one of our greatest 

 hindrances at present lies in the careless thinking which 

 fills our literature with wrong or at least misleading 

 imaginings, such as are suggested by the Jonah-like 

 words, adaptation, use, purpose, etc. It is to certain 

 lines along which improved methods of measurement 

 seem desirable that I wish to call your attention at the 

 present time. Our methods for dealing with the plant re- 

 sponses, with the effects of environment, already possess 

 a general accuracy far surpassing that exhibited by the 

 methods employed in measuring the environmental con- 

 ditions which act as causes. I am unable to avoid men- 

 tioning, however, one phase of plant measurement which 

 has so far received an almost insignificant minimum of 

 attention, both from physiologists and ecologists. I refer 

 to the subterranean portions of the plant. The relations 

 existing between the environmental factors and the de- 

 velopment and behavior of underground stems have 

 been studied for some forms by Vochting, Klebs and 

 others. Boots have usually been studied in water or in 

 air and only in the last few years has their behavior in 

 the natural medium, the soil, been seriously taken up. 

 A number of agriculturists have attacked the problem 

 here suggested, but of course with reference to cultivated 

 plants. Freidenfeld has made, as far as I am aware, the 

 first attempt at a really broad study of the ecology of 

 roots. The work of Dr. Cannon on the root systems of 

 desert plants shows how extremely important subter- 

 ranean competition may sometimes be. It would seem 



