wo 
STUDIES IN ROOT-PARASITISM. 
distinction between its haustorium and those of Olax and 
Santalum. 
The cortical folds have ceased to grow at their edges and 
a growing point can no longer be traced. But a well-marked 
group of cells is found in the thickness of the fold, whose walls 
have evidently undergone some change (j). These walls are 
not stained by hematoxylin and thus present a yellowish 
patch of tissue in the surrounding violet. The addition of 
anilin sulphate causes them to assume a bright yellow colour, 
with chloroiodide of zinc they turn brown and with phloro- 
glucin and hydrochloric acid they become pink. These and 
other tests show them to be lignified. The walls are thickened 
and pitted and their presence in this region is typical of most 
Cansjera haustoria. 
The nucleus, as might be expected from the important 
part played by it in penetration, shows the greatest changes. 
The cells in the upper part have enormously increased in size, 
so as to greatly exceed those of the ground tissue above them, 
and have become distinctly elongated in the direction of the 
sucker. They form a striking feature in all sections of haus- 
toria at this stage, and have large nuclei and nucleoli imbed- 
ed in deeply staining granular protoplasm. Their cell-walls, 
on the other hand, are extremely thin and difficult to dis- 
tinguish. The appearance of these nucleated cells is so remark- 
able that a question as to their function naturally arises. It 
does not seem sufficient to assign to them a merely nutritive 
or mechanical action in forcing the sucker downwards into the 
host. The cell contents are very like those of glandular organs. 
A study of the drawings in Plates IV and V (d', d, a, a', and a) 
will indicate successive stages in their development, and it may 
be noted that they appear most like glandular cells at the moment 
of penetration. We have seen that the nucleus of the haus- 
torium in Olaz is practically all taken up in the formation of 
the gland, and it appears probable that the same is the case» 
although in a different manner, in Cansjera. The slit-like 
‘*sland’’ (e) then assumes more the character of a duct, and the 
