The Evidence from Hybrids. 121 



of what might have been expected from their parent- 

 age. 



" Professor Lecoq speaks strongly to the same effect 

 in regard to this same genus, and asserts that many of 

 the hybrids from Mirabilis jalapa and mnltifiora might 

 easily he mistaken for distinct species, and adds that they 

 differed in a greater degree than the other species of the 

 genus from M. jalapa. Herbert has also described thcf off- 

 spring from a hybrid Rhododendron as being as unlike 

 all others in foliage as if they had been a separate species. 

 The common experience of floriculturists proves that 

 the crossing and recrossing of distinct but allied plants, 

 such as the species of Petunia, Calceolaria, Fuchsia, 

 Verbena, etc., induces excessive variability: hence the 

 appearance of quite new characters is probable. M. Car- 

 riere has lately discussed this subject; he states that 

 Erythrina cristagalli had been multiplied by seed for 

 many years, but has not yielded any varieties; it was 

 then crossed with the allied E. herbacia, and the resist- 

 ance was now overcome, and varieties were produced 

 with flowers of extremely different size, form, and 

 color." 



Darwin, therefore, concludes that crossing, like any 

 other change in the conditions of life, seems to be an 

 element, probably a potent one, in causing variability. 



The variability of hybrids is quite as explicable by 

 Darwin's Pan genesis hypothesis as it is by our theory of 

 heredity, although I do not see why, on the hypothe- 

 sis of pangcnesis, the hybrid offspring of domesticated 

 forms should be any more variable than those produced 

 between wild species. 



