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1893.] 
Cell Union in Herbaceous Grafting. 289 
ing through the young cells at right angles to their longer 
. The free sides of these growing cells were much more 
thickened than the others (fig. 8). 
The cross section of another graft of potato on tomato 
_ showed the central parenchyma of the tomato joined to the 
soft bast, cambium and fibrovascular bundles of the potato. 
Although the line of union was marked by a slightly thickened 
wall, no gaps were present and no development of meriste- 
matic tissue occurred. The junction of the two members was 
*0 neat as to be no more marked than the transition from one 
issue to another in the same plant (fig. 9). 
previous grafts of potatoes and tomatoes. Thickened brown 
~~ senerally marked the junction of the tissues, asin the for- 
‘grafts; in some instances where gaps existed in this wall 
the cells of th 
obliterate the path of the knife. In such places the 
longer axes of the cells were nearly at right angles to the line 
Junction (fig. 10), 
Apap and tomato grafts.—Geranium scions were easily 
stance me tomato stocks, the geranium in nearly every in- 
eal ree and increasing in foliage. The tomato scions 
no instance, however, accomplish union with a 
The repeated trials proved that in respect 
explanati lants do not act reciprocally. As a par- 
in the relati ton of this two facts are offered, viz: nese 
en oo quantities of sap in tomato and geranium, an 
Tee acidity. The geranium has relatively much less 
tomato and in addition to this the sap is of greater 
have hg Sections of these grafts showed the geranium to 
* OS ip aibe active in the formation of the union (fig. 11). 
. m 
With and 
on ; re ae 
ne the geranium Was more active in forming the union, 
. 
potato grafts. Successful grafts were made y 
Pe Sranium Scions to potato stocks. In this case as in the 
