HOETICULTURE. 949 



l»y their roots. The rose and the grape have also been united. Never- 

 thel(\ss, the graft by approach does not always succeed between phmts 

 so different. Thus the author endeavored in vain to graft the horse- 

 chestnut and the common chestnut. 



The author considers anak)gy in cell contents as affecting the graft 

 1)V approach, and it is shown that the accumulation of reserve material 

 in different vegetative^. ]:>arts of plants has no special importance in 

 grafting, as is proved by the success attained in grafting by approach 

 the turnip and cal)l)age, borecole and kohl-ra])i, Brussels sprouts and 

 kohl-rabi, and kohl-i-abi and cauliflower. Even grafting by approach 

 l)etween roots of lettuce and aged salsify succeeds, though the inulin 

 of the salsify roots is not al)le to circulate in the cell membrane of the 

 lettuce. But if the cell contents of one of the plants approached are 

 toxic for the other, the graft fails. Thus the author was not able to 

 graft celandine and salsify, salsify and burdock, etc. 



Under analogy in method of development, it is shown that if a large 

 and a small variety are grafted on each other, the larger variety will 

 develop to the detriment of the smaller, which will remain nearly 

 dwarf. Plants of different forms, like borecole and cauliflower, may 

 make good unions. Plants in active condition of growth may be 

 grafted by approach on plants at rest. Thus a seedling cabbage several 

 weeks old was grafted in the spring time on a turnip, the root of which 

 was already completely formed. The graft succeeded perfectly. The 

 graft b}' approach succeeds between annuals, ])iennials, and perennials. 

 Thus peas, sweet peas, and toad flax have been united. The symbiosis 

 ceased at the death of the annual species. The same fact was observed 

 in grafting l)y approach l)iennial and perennial plants. The success of 

 the graft between the flr and the linden, and AraUn spiiiom and A. 

 deboldii^ shows that deciduous and evergreen plants may l)e grafted 

 on each other. 



With the graft proper, as with the graft by approach, all of the 

 extrinsic conditions, such as temperature, rotting and drying of the 

 meristem, and necessity of contact of the wounds, are present, but in 

 cutting off' the top of the stock and suppressing the absorbing appa- 

 ratus of the scion there is danger of the death of both plants. Another 

 fundamental extrinsic condition of success, then, must be the main- 

 tenance of the life of the two plants until success is complete. The 

 scion is sometimes preserved by placing it in water as soon as it has 

 been prepared. This prevents it from drying out, keeps the cut 

 surface clean, and prevents the formation of sugar or other materials 

 on the cut ends which might interfere with the free passage of sap 

 from stock to scion, and is recommended. 



In order that the scion may be able to grow, it is necessary to rees- 

 tablish the turgescence of its tissues. This reestahlisiiment is made by 

 imbibition of the crude sap of the stock l)y the cells of the scion. The 



