96 HYBRIDS AND CROSSBREDS. 



two distinct varieties of the same species be in like manner 

 intermixed, the seed which results from the operation will be 

 intermediate between its parents, partaking of the qualities of 

 both father and mother. In the first case the progeny is 

 hybrid, or mule ; in the second it is simply crossbred. 



In general, crossbreds are capable of producing fertile seed, 

 and thus of perpetuating one of the species from which they 

 sprang. Hybrids, on the contrary, are often sterile, and 

 therefore incapable of yielding seed. 



Reasoning from a few facts, and from the analogy of the 

 higher orders in the animal kingdom, it has been believed that 

 all vegetable hybrids are sterile ; and, when sterility is not the 

 consequence of the intermixture of two species, it has been 

 thought that such species are not naturally distinct, however 

 different their appearance. But facts prove that undoubted 

 hybrids may be fertile ; and when we consider that plants are 

 not analogous to the higher orders of animals, but to the 

 lowest, concerning whose habits we know little, it is obvious 

 that no analogical inferences can be safely established. 



