'Budding,' as used for propagation of Roses: a young bud, with attached 

 cambium-layer ' shield ', slipped in T-opening of cortex of another stock : the cam- 

 biums unite and the wound heals leaving bud attached to stock. 



Stem-grafting : a young shoot with buds (scion) cut to fit stock, in form giving 

 broad range of cambial approximation (cleft-grafting, whip, and ' saddle '-grafting) ; 

 the whole kept warm and damp to reduce transpiration, until the wound i- 

 (clay, wax, or earthing-up). Utilized for Fruit-trees, Conifers as Araucaria, Cupres- 

 XKJ, and Forest trees. Plants are said to be ' worked ' on the stock. Many vars. m;iy 

 be put on the same individual : cf. Ornus on Common Ash, Mespilus on Hawthorn, 

 Zflkava on Kim, Coryhis Colurna on Hazel. 



Boot-grafting, often more effective since the whole may be kept d;imp in well- 

 aerated soil ; cf. Clematis vars., Paeonia. 



Herbaceous Grafting, more readily effected when the tissues are of undifieren- 

 tiated parenchyma and cambium is active ; cf. Tomato on Potato, Cucumber on 

 Veg. Marrow ; less useful owing to short life of host : more effective in case of many 

 succulent Cacti. 



Theory of Grafting: The cambiums and parenchymatous tissues of graft 

 and stock unite in a common wound-callus ; this may differentiate wound-tracheides 

 putting the water-supply in continuity, but always making a more or less bad join ; 

 no primary connexion of vessels or sieve-tubes ; only water and solutions pass to the 

 scion, hence water-supply of latter is always pinched at the junction ; tissue-union 

 may be more complete later. Consequences follow : the water-supply of the scion 

 is affected by that of the stock ; e. g. a stock with vigorous root-system may give 

 a scion of xeromorphic habit a better supply than it had before ; the graft then grows 

 vigorously (' enlarging ') : more usually (commercially), on a stock with less root- 

 activity, the scion is distinctly more xerophytic than before, and the balance of photo- 

 synthesis against proteid-synthesis is increased; e.g. giving (i) reduced vegetative 

 growth, (2) early flowering, precocity in fruiting, (3) abundant fruiting, (4) fruits 

 larger, sweeter, and often more highly-coloured (anthocyan and carotin pigmentation), 

 hence ' ennobled ' ; cf. Apples worked on a stock with fibrous roots, Pears on Quince. 

 Note: Similar periodicity is more essential than affinity (Columella), but in 

 inferior climate the latter is the readiest way of getting the former. Merely grafting 

 a shoot back on the same individual gives an improved effect ; the result may be empha- 

 sized by * double-grafting '. Similar ' ennobling ' phenomena may be produced by 

 ringing the tree, or constricting the cambium by tying a string round it. 



Influence of the graft on the stock, and vice versa, is apparently confined to the 

 translocaiion of readily diffusible substances ; but interesting cases may be noted ; cf. 

 variegated Laburnums. Connexion is solely nutritive. 



Plant Chimaeras : Of great interest as bearing on the question of the union of 

 cells and plasma of scion and stock. Commonest case is that of Cytisus Ac/ami : 

 C.purpureus grafted on common Laburnum (1826) gave a shoot intermediate in all 

 respects, in branches, leaves, flowers, and inflorescence-characters, so far unlike 

 a hybrid. Also marked reversions to the two ' parents', so that 3 types of branch, 

 leaf, and flower, in different colours, are produced on the same tree. Propagated 

 still by grafting C. Adami on Laburnum. 



Cf. also Crataego -Mespilus of Bronvaux (Metz), as Medlar on Hawthorn, with 

 5 types of flower, 2 components, and 3 intermediates. 



Explained by ' Chimaeras ' of Solanum on Tomato (Winkler, 1 908) ; herbaceous 

 grafts with free production of adventitious buds from stock when headed back. On 

 cutting back a grafted specimen through the graft-junction, occasionally a bud starts 

 on the line, with apex compounded of cells from either side ; the resultant shoot may 

 be a Chimaera, of one type down one side and the other type on the opposite side, 

 even to demarcation along one leaf of the spiral phyllotaxis common to both. Others 

 give more intimate fusions, cf. sectorial, periclinal, and blended Chimaeras : these 

 also show phenomena of reversion, and C. Adami is regarded as a periclinal chimaera, 

 with the Laburnum cortex and stele enclosed in C. purpureus dermatogen. Note, 

 however, that reversion to the latter is still obscure, as also sectorial reversion (cases 

 may vary in different apices). Protoplasmic continuity obtains between all the 

 tissues ; hence may illustrate vegetative union or plasmogamy, as opposed to syngamy 

 of a true hybrid. 



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