118 STATE HORTICULTURAL SOCIETY 



main vaiiation, and by this variation we get iniprovenient; that is, we 

 get individuals whicli are vastly sui)eriui- to those with which we start. 

 On the other hand, we have the asexual method of reproduction; that is, 

 the reproduction of individuals by division, by budding or cuttings. The 

 sexual method of reproduction has in some species been lost, and we go 

 on propagating them asexualh. The propagation of nuiny of our culti- 

 vated plants is purely asexual. vSome of the species have lost the power 

 of propagating by a sort of budding process. 'The question of bud varia- 

 tion and the variation of dift'erent branches on the tree is so complicated 

 that I do not care to undertake to discuss it now. It is only under com- 

 paratively exceptional cases that bud variation is prominent or striking 

 enough to concern horticulturists. So, to answer that question, we should 

 say that i)ropagation by asexual methods should give a constant stream 

 of individuals, barring the possibility of bud variation, and the whole 

 question then will come back on the asexual method and the question of 

 sexual methods — whether you may, in selecting buds, get inferior or 

 superior ones, and so on. In that case there would be just as much 

 possibility of miming the plant up as running it do\^ n, by selecting the 

 buds. 



Mr. Morrill : That W'ould lead you on to the effect of scion on graft, 

 w'ould it not? Prof. Waite: I hardly think so. 



Mr. Morrill: You would drop into that. 



Prof. Waite: You might drop into that, too, but I am very much in- 

 clined to believe mjself that the effect of scion on graft is a mere matter 

 of nutrition. I might add one idea to what was brought out last night. 

 That is, that the nutrition is not merel}' a nutrition of the top of the 

 tree, of the scion, by the root, but is more strikingly' the other way, the 

 nutrition of the root by the top. The assimilation of food, the building 

 up of food material, is all done by the leaves. In other words, the nutri- 

 tion of the tree comes down instead of going up. Some material is taken 

 up from the roots, mainly water, through wliicli are absorbed the mineral 

 constituents (those come up to the leaves) and in the leaves the assimila- 

 tion takes place. All the woody matter, for instance, is brought up. It 

 is true, however, that the comparatively small quantities of mineral mat- 

 ter brought up by roots, and all nitrogenous materials that are ab- 

 sorbed in that way, are factors in the development of the plant. They 

 are the things that decide generally how vigorous it shall be; but the 

 actual assimilation of the starch and sugar that go to make the wood and 

 the fruit, the great bulk of the fruit material, is done in the leaves, so that 

 we expect the top to have more influence on the root than the root on 

 the top, and I think that is the case. To come back to the sexual method, 

 by seed, we have great possibilities of running plants up or down, be- 

 cause the seedling is not exactly the same as the parent, and the only 

 wonder is that we can hold our horticultural varieties which are propa- 

 gated by seed as well as we do. It is a well-known fact that we do not 

 hold them (Prof. Tracy will vouch for this); that none of our horticultural 

 varieties propagated by seeds can, from the very nature of the case, be 

 permanent. They are mere matters of selection each year, and it depends 

 entirely on the skill of the seed-growers as to how nearly a variety is 

 retained to its type, or whether it is im])roved or whether it retrogrades. 

 Generally they are supposed to improve them, but they do not always 

 succeed in that. 



