hi^ Hybridisation 343 



but nevertheless reappear unchanged in their pro'^^eny, as 

 will be demonstrated later on. 



It was furthermore shown by the whole of the experi- 

 ments that it is perfectly immaterial whether the dominant 

 character belong to the seed-bearer or to the pollen-[)arent ; 

 the form of the hybrid remains identical in both cases. 

 This interesting fact was also emphasised by Gartner, with 

 the remark that even the most practised expert is not in a 

 position to determine in a hybrid which of the two parental 

 species was the seed or the pollen plant*. 



Of the differentiating characters which were used in the 

 experiments the following are dominant : 



1. The round or roundish form of the seed with or 

 without shallow depressions. 



2. The yellow colouring of the seed albumen [coty- 

 ledons]. 



3. The grey, grey-brown, or leather-brown colour of 

 the seed-coat, in association with violet-red blossoms and 

 reddish spots in the leaf axils. 



4. The simply inflated form of the pod. 



5. The green colouring of the unripe pod in association 

 with the same colour in the stems, the leaf-veins and the 

 calyx. 



6. The distribution of the flowers along the stem. 



7. The greater length of stem. 



With regard to this last character it must be stated 

 that the longer of the two parental stems is usually exceeded 

 by the hybrid, a fact which is possibly only attributable to 

 the greater luxuriance which appears in all parts of plants 

 when stems of very different length are crossed. Thus, 

 for instance, in repeated experiments, stems of i ft. and 

 6 ft. in length yielded without exception hybrids which 

 varied in length between 6 ft. and ']\^ ft. 



The hybrid seeds in the experiments with seed-coat are 

 often more spotted, and the spots sometimes coalesce into 

 small bluish-violet patches. The spotting also frequently 

 appears even when it is absent as a parental character t- 



The hybrid forms of the seed-shape and of the allnmun 

 [colour] are developed immediately after the artificial terti- 



* [Gartner, p. 223.] 



t [This refers to the coats of the seeds borne by F^ plants.] 



