292 HYBRID PLANTS. 



452. When a plant is raised from seed, it will always bear 

 a strong likeness to its parent ; and if the species be one which 

 lias little tendency to variation, it will resemble it very closely. 

 But there are many species, which have a great disposition to 

 present deviations, from what may be considered their original 

 form (. 13 16); and thus, from the seeds of the same parent, 

 it is often possible to produce, by a difference of treatment, a 

 number of plants differing considerably from one another. What- 

 ever such differences may be, however, these plants are all re- 

 garded as belonging to the same species, since they are descended 

 from a common stock ; and by such experiments, it may be 

 often shown that plants, which have been considered as distinct 

 species, have no real title to be so classed (. 16). 



453. It is often possible, however, to produce seeds capable 

 of giving origin to plants, that shall combine the characters of 

 two different races. This is done, by placing the pollen of one 

 species upon the stigma of another ; so that the germ, furnished 

 by one, shall be nursed (as it were) by the other. It is not 

 difficult to understand, how the germ thus influenced, should be 

 subsequently developed into a form, differing from that of its 

 own parent ; for the germs of Cryptogamia, which are not re- 

 ceived into any ovule, but are dependent upon the elements 

 alone for their support, are often developed (especially among 

 the lower tribes) into forms very different from that which they 

 would naturally present. Thus a Mucor, a sort of Fungus con- 

 cerned in the production of mouldiness, has been seen growing 

 in water, in a form so like that of a Conferva, that it was only 

 recognised as a Fungus, when it lifted up its fructification above 

 the fluid. 



454. The plant developed from a seed produced by the agency 

 of two races, is termed a hybrid. It is necessary, in order that 

 the seeds thus formed should be fertile, that the parent species 

 should be nearly allied to each other ; and it is very seldom that 

 a hybrid can be produced, when they do not belong to the same 

 genus. Now, if the hybrid bear flowers, and its stigma be fer- 

 tilised with its own pollen, it may produce seeds that can be 

 raised into plants like itself; and these may flower and produce 



