90 MR. C. DARWIN ON THE DIMOKPillC CONDITION 



Primula auricula, — Table III. 





Short-styled by own-form pol- 1 



len (homoru Orphic union) ., J 



Short styled by pollen of long- 1 



styled (heteromorphic union) J 



0-12 

 1-50 



, Weight of 

 Good } seed in 

 Pods. ^ grains. 



or as 100 to 12 

 or as 100 to 50 



Whoever will study these three tables, which give the result 

 of 134 flowers carefully fertilized and protected, will, I think, be 

 convinced that in these three species of Frinnila the so-called 

 heteromorphic unions are more fertile than the homomorphic 

 unions. For the sake of clearness, the general result is given in 

 the following diagram, in which the dotted lines with arrows re- 

 present how in the four unions pollen has been applied. 



Heteromorphic union. 

 Complete fertility. 



Homomorphic 



union. 



Incomplete 



fertility. 



Homomorphic 



union. 



Incomplete 



fertility. 



"We here have a case new, as far as I know, in the animal and 

 vegetable kingdoms. We see the species of Primula divided into 

 two sets or bodies, which cannot be called distinct sexes, for both 

 are hermaphrodites ; yet they are to a certain extent sexually 

 distinct, for they require for perfect fertility reciprocal union. 

 They might perhaps be called sub-dioicous hermaphrodites. As 

 quadrupeds are divided into two nearly equal bodies of different 

 sexes, so here we have two bodies, approximately equal in number, 



