-No. 640] BODY SIZt] AND ORGAN SIZE 387 



These authors generally agree that there is a positive, 

 though small, correlation, usually of about the magnitude 

 of .2 to A, between the size of the plant, as measured by 

 height or by yield, and the average weight of the seeds 

 it produces. Larger plants also tend rather consistently 

 to have larger heads. 



In two extensive memoirs on oats in 1914 Love and 

 Leigh ty (10) and Leighty (8) presented an abundance 

 of data on this problem. In the former paper the authors 

 find positive and fairly large correlations between the 

 size of the plant, as measured by yield, and the size of 

 each head, as measured by its individual yield or by the 

 number of spikelets or number of kernels which it pro- 

 duces. The average weight of kernel per plant is not 

 very consistently correlated with any character repre- 

 sentative of plant size, however, although most of the 

 correlation coefficients are positive and many are, in cer- 

 tain seasons, significantly large. In the second paper 

 the author, working with another variety, finds consist- 

 ent, positive and significant correlations between plant 

 height and average weight of kernels. He points out 

 that the degree of correlation in all characters studied 

 increases considerably as the plants are reduced in size 

 through crowding. 



Arny and Garber (1) in 1918 found that, in wheat, 

 plant height and plant yield are positively correlated 

 with spike length; and that average kernel weight is 

 positively and consistently correlated with yield (total 

 kernel weight) and with number of kernels. The authors 

 mention unpublished work of Atkinson and Hutchinson 

 who found substantially the same results. 



With corn, the reports are somewhat conflicting. 

 Ewing (2) found a positive but small correlation between 

 yield and leaf length and breadth. Hutcheson and Wolfe 

 (6) found a sii^nificant correlation between yield and both 

 length and riiciinifoi onco of ear. Olson, Bull and Hayes 

 (13) and otlici-s, liowov^-, find no significant correlation 

 between yield and any other character studied. 



