290 The Botanical Gazette. (Angee, 
as shown by the cells along the line of junction of the two 
members (fig. 11). In this graft the wall which marked the 
line of union was thickened but otherwise similar to ordinary 
cell walls. 
Cactus grafts.— Cactus grafts were made, and sections 
showed the method of union to be essentially like that inthe 
other cases studied. The union occurred in either one or the 
other of two ways: long continued pressure holding cell wilt 
in contact gradually causing them to cohere, or through tht 
development of meristematic tissue by each member. 
stock. In grafting tradescantia to itself the members of the 
cells elongated towards the gap and divided, 
new cells until the space was closed and the revious 
plished through pressure of the cell walls as in P ee 7 
Union of tradescantia and tomato.—In spines found to * 
graft of tradescantia upon tomato the union ene <i el 
as perfect as any between tomato stock and wee evidence 
Many places tissues of both members or outlying 
marked activity in forming union, in others t ti 
of border cells were thickened and union wait wallsupo" 
have been the result of pressure of the border ce™ ing 
other. The tomato was the more active } 
union (fig. 12). : us in 
Examinations of callus. Examine pros sand, 
and potato slips, which had been placed between ns 
made in order to see what relation exists wounds 
of these external wounds, and of the intern tee 
unio 
S. 
