PROPAGATION. 143 



a long time after that of the ovule, and that the em- 

 bryo is attached to the summit of the latter by a cellular 

 cord or funiculus. 



247. In summing up, Mr. Griffiths observes, that 

 this remarkable fact of the formation of the ovule after 

 impregnation, tends materially to increase the difficulty 

 of comprehending or even forming a conjecture upon 

 the nature of the first degree of the formation of an 

 embryo. It is evidently in complete disagreement with 

 the idea that the ovule is a receptacle adapted or neces- 

 sary for the development of the embryo, which, accord- 

 ing to this opinion, is supposed to proceed entirely and 

 directly from the anther. 



248. Endlicher seems to have been the first (at least 

 according to his own work dedicated to Dr. Brown,) 

 who had his doubts of the truth of the hitherto re- 

 ceived opinions of the generation of plants, and has 

 promulgated that the anthers are to be likened to the 

 ovaria of animals, and the ovulum to the uterus ; but 

 that the male organ is to be looked for in the stigma. 



249. Before concluding this part of the subject, we 

 may remark, that the power of generating hybrids ex- 

 ists in the vegetable as well as the animal kingdom ; and 

 in the former the instances of mules are of far more 

 common occurrence than in the latter. 



250. It is said that more pollen is required to ferti- 

 lize a plant in the way of Hybrid generation, than in 

 the regular manner, and that the plants produced are 

 only fertile themselves to the third or fourth generation. 



251. Propagation. Plants may be propagated in va- 

 rious ways by slips or cuttings, layers, graftings, and 

 bulbs, etc. In propagating by slips, a portion is cut 

 from the plant intended to be propagated, and either 

 placed at once in the ground, or else upon a cut sur- 

 face on another tree of the same family, the latter 

 process being called grafting. In grafting, the slip 

 cut from the tree to be propagated, is called a scion, 

 and the tree upon which it is placed, the stock ; 



