90 MR. C. DARWIN ON THE DIMORPHIC CONDITION 
Primula auricula.—TAnrE III. 
EK s.l if Weight of 
ued) SSG) 22 ei te) 
FEPER EE 
8 a zs E 7- Ep - | grains. 
Short-styled by own-form pol- 9 1 0-12 | or as 100 to 12 
len (homomorphic union) .. < l 
Short styled by pollen of long- « . n 
styled (heteromorphic unio ] 3 3 1°50 | 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 Primula 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. 
a Eoee </ 
Homomorphic / V Homomorphic 
union. i ^ union. 
Incomplete \ Incomplete 
fertility. | fertility. 
L 
t 
i 
1 
' 
1 
a 
a 
n 
iY 
\ 
` 
T 
| 
| 
| 
| 
| 
Complete fertility. 
M ---------- nae > || 
| Heteromorphic union. 
Long-styled Short-styled 
Form. Form. 
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, 
