950 EXPERIMENT STATION RECORD. 



reestabli.shment of turoescence is effected more quickly according as the 

 crude sap is presented in considerable quantity, but also more quickh' 

 if the initial turgescence of the tissues of the scion has not been dimin- 

 ished during- the preparation of the graft and its putting in place. 

 This explains why it is necessary to operate (piickly and why the cut- 

 ting of the graft under water, Avhere the scion preserves in a large part 

 its turgescence, produces such good results. It also accounts for the 

 good effects of the waxlike matei'ial in grafting in the open air; the 

 utility of the collar graft, because the osmotic force is strongest at this 

 level; and the importance of the time of day in operating, because the 

 osmotic force varies in the course of the day, being strongest in the 

 evening (hence the greater success of grafting in the evening). The 

 reestablishment of the turgescence in the graft is cited as a funda- 

 mental condition of success, therefore it is not possible to graft parts 

 of plants which are incapable of retaking their turgescence or which 

 do not possess it entirely. 



Under intrinsic conditions, it is shown that in the graft proper, as 

 in the graft b}" approach, plants incapable of regenerating their tissues 

 can not be grafted. The author succeeded in grafting hy the graft 

 proper the white lily, (lladiolus, F(nicMa cordata^ etc., when operating 

 on young stems. In all these grafts the anatomical cicatrization was 

 effected b}- the parenchymatic tissues. No liber or fibro vascular 

 structure was observed to form between scion and stock. The trans- 

 port of the sap was thus singularly hindered, and at the end of a vari- 

 able period one of the parts, or both, died. By utilizing the aerial 

 roots, which some of the monocotyledons possess, to supplement the 

 absorption of the scion, success was attained with a numl)er of plants. 

 This shows that the nonsuccess of the graft with monocotyledons 

 capable of regenerating their tissues comes from insufficient vascu- 

 lar counuunication, since it becomes possible when a complementar}' 

 absorption apparatus is supplied. 



Plants with active cambium layers, which may be grafted by 

 approach, can not always be grafted by the graft proper, since the 

 common European bean {Faha 'vulgaris) and the kidney bean, which 

 graft easily by approach, have always failed when grafted l)y the gi-aft 

 proper, no matter what precautions were taken. 



Differences in wood and bai'k are not obstacles to success in the graft 

 proper. Thus there is a great difference in the thickness and strength 

 of the safflower and the annual suntlower; between the sunflower and 

 the .Jerusalem artichoke; the young cabbage and the root of the tur- 

 nip; the root of the cultivated carrot and that of fennel; nevertheless, 

 these plants united perfectly. These same facts were observed with 

 trees, the graft succeeded between the chestnut and the oak, the pear 

 and the hawthorn, the hawthorn and the quince, in spite of the marked 

 differences in the barks. From these and other grafts, it is concluded 



