60 Heterostylism in Oxcdis 



These figures increase our knowledge on certain points. 



(1) There is no evidence against the supposition that male and 

 female gametes of a plant are carrying the same qualities. Compare 

 A and A' etc. In the four groups A — D there is good agreement 

 with their reciprocals A' — D\ 



Note, however, the excess of Shorts in B, and the excess of Mids 

 in F. 



(2) Two of the three Shorts used are similar in constitution (9/1 

 and 70/5). It was not possible to cross the third Short with any of 

 the Mids used with 9/1 and 70/5, so no comparison can be made. 



(3) The seven Mids used can be classed according to their offspring 

 when crossed with the same Short. 



Four different Mids were used with the Short 9/1; — giving: 



Longs 

 „ 

 8 „ 

 10 „ 



28 Mids : 25 Shorts Cross 1 Mid-parent 9/2 



30 „ : 24 „ „ 11 „ 9/3 



8 „ : 8 „ „ 14 „ 70/4 



17 „ •:29 „ „ 20 „ 37/1 



Again these four Mids were crossed with the Short 70/5 ; — giving : 

 Longs : 33 Mids : 21 Shorts Cross 4 Mid-parent 9/2 

 „ :43 „ : 39 „ „ 3 „ 9/3 



84 „ : 76 „ : 133 „ „ 6 „ 70/4 



8 „ : 4 „ : 10 „ „ 5 „ 37/1 



Clearly the Mid-parents 9/2 and 9/3 are similar, and differ in con- 

 stitution from 70/4 and 37/1. 



In the case of the remaining three Mids used as parents for the 

 i^4 generation, there is no comparative evidence on their conformity 

 with one or other of the above classes, or on the possibility of their 

 representing a third type of Mid-styled plant. 



TABLE VL 



Showing the ratAos given hy the four Mid-parents crossed with two 

 similarly constituted Shorts; and of the three remaining 

 Mid-parents crossed with Shorts of unknown constitution. 



