No. 629] DARWIX AXD HYBIUDIZAriOX 545 



Darwin finally also remarks in general : 



I lie rclatiNc weiglit and ^ermmative energv of seeds 

 from crossed and from self-fertilized plants, was inves- 

 tigated by Dai-win m the case of sixteen species, with the 

 result that the weight of the seeds of the former to that of 

 the latter was found on the average to ho as 100 :0(). In 

 ten out of the sixteen cases the self-fertilized scods were 

 either equal or superior to tlie crossed in wt-iulit. Imt in 

 six out of these ten, the i:)lants raised fioin tlie-c -olfed 

 seeds were greatly superior in lieiu'lit and in ittlicr re- 

 spects to those from the crossed -ccd^. In llir mattt'i- of 

 germination of selfed and cr(.>>cd -(mmU. ilic r.wnlt^ were 

 conflicting. Darwin, however, di>c()Ver;'(l ihat, in unieral, 

 seedlings of greater coiistitntidna! Nigoi' are ehtained 

 when crossed hy otli.n- indivi.hial< of tlie ^anie >tcck. than 

 when po]linate<l hy tlieir own pollen. 



In the cases of plants of lifty-seven diffeivnt >)H'eies, 

 belonging in all to fifty-two genera and thirty different 

 families, Darwin carried out the most exten>i\c exper- 

 iment 5^et recorded, conducted for the ])iiri)ose of deter- 

 mining the differences in size, between the offspring of 

 cross-fertilized and of close-fertilized plants. 



The total number of the crossed plants amounted to 

 1101, and of the selfed plants to 1076. As a result, Dar- 

 win found that tlie ])lants derived from crosses between 

 different stiains of the >anie species, were taller on the 

 average, than plants derived from crosses within the 



