8 OBSERVATIONS UPON MULING AMONG PLANTS. 



pregnation, though the forms are identical, whichever parent be 

 male or female, and tlie colours generally the same, a change in 

 this respect does occasionally take- place. Mr. Herbert's notion, 

 therefore, that the male parent gives the tone to the colouring 

 of the mule is certainly untenable. 



In mixed mules, where the pure species is also the female 

 parent of the mule with which it is impregnated, the change of 

 colour is so variable, that scarcely two plants from the same 

 seed exhibit the same colouring. This, consequently, is the 

 most fruitful source of the florist's varieties. In compound bas- 

 tards, where there are three parents, the mules generally assume 

 the tone of the new male parent. 



Not unfrequently flowers of different hues occur in the same 

 plant, as in Mirahilis and Dianthus barhatus. It has been sup- 

 posed that tliis arose from the influence of strange pollen on the 

 blossoms and ovaries : but as the blossom is exj^anded before the 

 access of the pollen, this cannot be the case. The cause of this 

 variety of colour is at present altogether obscure. 



The colours of the capsules and seeds are often altered by 

 hybridization. We have already said that Pisum appears to be 

 the only genus in which the tint of the seeds is immediately 

 affected by impregnation, alterations in general not being appa- 

 rent till the succeeding generation. The common Maize exhibits, 

 after hybridization with forms possessing differently coloured 

 seeds, not merely differently coloured spikes, but spikes bearing 

 variously coloured seeds. No immediate alteration, however, 

 was effected as in Pisum, and the same may be said of Lyclinis 

 diurna and vespertina, of which the former has reddish brown, 

 the latter cinereous seeds. These facts confirm the general law, 

 that the influence of the strange pollen in hybridization makes 

 no alteration in the peculiar form and external peculiarities of the 

 fruit and seeds of tiie mother plant, but merely produces in the 

 embryo, after germination and in the course of its development, 

 a capability of producing a mixed product from the concurrence 

 of the two factors. 



As in the case of flowers, party-coloured or differently coloured 

 fruits exist .sometimes on the same stem. Such phenomena do 

 not appear, however, to be the effect of hybridization, but to be 

 ascribable to the tendency of plants to produce varieties. With 

 regard to the fructifying organs, the male are affected more than 

 the female. The number is often increased, but their fertility 

 impaired or wholly destroyed. The stamens, though externally 

 perfect, are often diseased and disposed to fade prematurely ; and 

 this not in a few blossoms only, but in all equally, while the 

 anthers are well formed, but for the most part sterile. Some- 

 times, indeed, they are smaller than in pure species, shrivelled 

 and discoloured, and contain no perfect granules, but merely an 



