ON THE UNION OF EMBRYOS. 



FROM THE gardeners' CHRONICLE. 



It will have been seen by a communication in our last number, that experimentalists 

 are puzzled to understand how it is possible to make two embryos grow together by 

 grafting. It seems to be considered impracticable so to unite the seeds of an orange and a 

 lemon as to blend them into one single plant from the very beginning of their growth. 

 Undoubtedly, the operation is attended with some difficulty. Skill, and a sound knowledge 

 of the nature and structure of seeds, are demanded of those who would perform it. For 

 that reason, indeed, it was, that we offered a valuable reward to the first who should succeed. 

 Had it been a mere puzzle, which could be solved by some lucky accident, we should 

 have consigned it to the limbo of rebuses, charades, and similar puerilities. But knowledge 

 and the power of applying it were demanded, and for this reason it apjieared to be an ex- 

 cellent subject for experiment ; certainly not merely for the sake of a trifacial orange, which 

 might be easily obtained in Alexandria. 



We have already stated, in reply to an inquirer, that it would probably facilitate the 

 operation if the surfaces to be united are pared down, just as is done when common grafts 

 are united. But we are by no means sure that this is indispensable. On the contrary, 

 many facts indicate that mere contact will produce the necessary union. No one can be 

 ignorant that cucumbers often come as 

 twins ; so do nectarines ; and we have 

 now before us a pair of Coe's Golden 

 Drop Plums completely united for about 

 half their length. In all such cases, no 

 removal of the surface of the parts took 

 place where they joined. They united 

 in consequence of being firmly pressed 

 together when very young, and in the 

 early stage of growth, while the tissues 

 were young, tender, and fonning fast. 



A similar example is presented by the 

 monstrous apple of which a figure is 

 annexed. In this instance, two apple 

 flowers, accidentally brought into close 

 contact in the earliest state of the bud, 

 being kept firmly in contact as they ad- 

 vanced in growth, ended by becoming 

 half incorporated ; notwithstanding 

 which, they finally became a twin fruit, 



consisting of two very unequal halves. In the smaller only four cells of the seed were 

 formed ; in the larger, but three. In other respects the structiire was complete ; but each 

 was furnished with a pair of elevated lines on the side next the line of junction, as shown 

 in the figure. The nature of these lines is unknown to us. Wliat is particularly deserving 

 of attention here is, that the hairy surface of the young apple flower offered no obstacle 

 to the junction in question ; possibly it took place before the hairs had formed. 



Such being the case, it becomes a question whether, in grafting seeds, it is at all necessary 

 that the embryos should themselves unite. It may be indeed conceived that the firm, solid, 

 highly carbonized, and scarcely azotized tissue of which such an embryo as that of the orange 

 consists, would, from its very nature, be unlikely to form an adhesion ; just, indeed, as 



Vol. YI.— August, 1856. 



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