142 PLANT HYBRIDIZATION BEFORE MENDEL 



In the matter of color intermediateness, he makes the state- 

 ment : 



"Once obtained, white coloration is able to serve, either by crossing 

 or by hybridization, in the production of new variations ordinarily in- 

 termediate between them and the color from which it has proceeded." 

 {ib., p. 59.) 



In other words, presumably, dilution through the presence of 

 but a single dose of the color factor. 



The most interesting portion of Verlot's memoir is his discus- 

 sion of the practical results achieved with ornamental plants in 

 the field of hybridization. 



Regarding dwarfing, he cites McNab (p. 42) to the effect that 

 the best dwarf varieties of Rhododendron are obtained by the use 

 of pollen taken from the small stamens : 



". . . the products of which," he says, "I am able to certify, are very 

 different from those obtained by the use of the pollen of the large 

 stamens." 



Regarding breeding for winter-hardiness, he mentions the case 

 of the cross of Amaryllis brasiliensis^ a delicate species impossible 

 to winter out of doors, by Amaryllis vittata, a much hardier 

 plant, whereby hybrids were produced which, with light cover- 

 ing, would withstand the climate of Paris. Likewise, Rhododen- 

 dron arhoreum^ which cannot resist more than two to three degrees 

 of cold, gave, when crossed by R. catawhiense — a much hardier 

 form, though with inferior inflorescence — hybrids which inherited 

 the hardiness of the female parent. 



Verlot did not recognize the phenomenon of dominance as such 

 in the first generation of the hybrids, but he mentions the case 

 of a white Gloxinia^ crossed by pollen from a blue-flowered 

 variety, in which, out of one thousand seedlings, 



". . . all bore nothing but perfectly blue flowers, not a single one of 

 them being white nor a single one variegated." (6, p. 65.) 



Regarding the inheritance of variegations, it may be of interest 

 to note that the following species are mentioned, in which the 

 variegated form breeds true from the seeds. 



Alyssum maritimum Celtis australis 



Bar bare a vulgaris Cheiranthus cheiri 



With these are to be included the variegated ferns Pteris ar- 

 gyraea and P. aspericaulis var. tricolor. 



