238 Boodle and Worsdell. — On the 
will be seen from the figure, they are different in shape from 
the cells immediately surrounding them, and seem to be 
pushing themselves by sliding-growth outward round the 
inner ends of the palisade-cells. A little further down in the 
same row is seen a very small representative of a transfusion- 
tracheide, which is rounded in shape and apparently quite 
isolated. 
These tracheides are often seen very well in a section which 
has passed through the phloem, and missed the xylem, or 
where, perhaps, only a single element or so of the xylem is 
seen. Such a case is that of Fig. 9. On the outer edge of 
the phloem occur rather narrow, longitudinally-elongated 
cells, which perhaps represent the endodermis. In the 
upper part of the drawing some of the assimilating cells 
abut on this layer. Lower down, however, is an element of 
a somewhat similar shape to the cells composing this layer, 
but rather narrower, very much pitted, and developed as 
a tracheide : it runs in a longitudinal direction, touching 
this layer on the outside. From this tracheide about four 
others, which are much larger, run outwards in a very oblique 
direction, and with their pointed ends press and push them- 
selves between the surrounding green cells. These green 
cells are probably situated on the inner side of the palisade- 
tissue somewhere near the base of the furrow. The tracheides 
which we have here figured are very typical representatives of 
this transfusion-tissue. They are rendered very conspicuous by 
their extremely thick walls and very numerous and closely- 
placed simple pits. The two last cases are taken from 
sections of C. glaucct , Sieb. In a section through the cortex 
of C- muric at a, Roxb., a straight, longitudinal row of these 
tracheides was observed, separated from the palisade-tissue 
by two layers of cells. Their tracheidal nature was seen, of 
course, by their lignified, pitted walls, and their absence of 
cell-contents, but also by the way in which they seemed to 
utilize every chance of obtruding themselves between the 
ends of the adjacent cells. In this place, however, their 
course was not at all oblique, and formed, probably, part of 
