320 



BIOCHEMICAL SYSTEMATICS 



Table 15-2. Percentage representation of each of three species in individual 

 plants of tri-hybrid population as indicated from morphological hybrid index, 

 (Alston and Turner, 1962). 



B. sphaerocarpa but only in the flowers. In hybrids of B. sphaerocarpa 

 X B. leucantha these four substances appear in unreduced amounts 

 in leaves as well as flowers. Apparently the regulatory mechanisms 

 which restrict the distribution of these substances in the pure species 

 are ineffective in the hybrid. This situation does not occur in other 

 hybrids involving B. sphaerocarpa, and the fact that it occurs in the B. 

 sphaerocarpa X B. leucantha hybrid indicates that possibly a greater 

 genome difference exists between those two species (Alston and 

 Simmons, 1962). 



A surprisingly large number of useful species-specific com- 

 pounds were discovered, especially in combinations involving B. 

 leucantha. For example, at least twenty reliable constituents distin- 

 guish B. leucantha and B. sphaerocarpa. 



