32 STUDIES IN ROOT-PARASITISM. 
in several sections cut through the roots of Capparis zeylanica 
and horrida. Further, in the wings of the host’s bark cut off 
by cork, the cells of which are browned and evidently decom- 
posed, it is not uncommon to find masses of starch grains while 
the rest of the cortex is almost quite clear of contents (Plate 
XI, figs. 1 and la). How are we to explain the presence of 
such quantities of stored carbohydrate in these places ? 
It might be suggested that, while the transverse connec- 
tion of parts in the attacked roots has been interrupted, a 
passage of substances might take place lengthwise. But longi- 
tudinal sections show that the dead cells of the wing are cut 
off in this direction by cork as well as across the section. It 
is, again, possible that the cortical cells were cut off at a time 
when all the tissues were charged with starch which has been 
subsequently translocated in the free tissues, but blocked by 
the cork in those cut off, or, indeed, that this very formation 
of cork or the formation of thyloses and gum in the vessels has 
taken up the superfluous starch. But a careful study of the 
sections does not incline one to this view, and this explanation 
could hardly be offered for the accumulation of starch in the 
yellow substance. 
It looks very much as if, in shese cases, the last act of the 
protoplasm, before or after the destruction of the cell-wall, 
was the deposition of starch from the excess of carbohydrates 
available from the action of the ferment in dissolving the cell- 
walls. We learn from Peirce’s observations on Cuscuta glo- 
merata attacking balsam leaves,* that the ferments act first on 
the cell-wall and last on the protoplasm, and that the meso- 
phyll cells are capable of forming fresh starch for a considerable 
period after they have been attacked by the sucker cells. It 
may be noted in passing that this accumulation of starch is only 
characteristic of attacks on certain plants. Thus in Morinda 
tinctoria, penetrated by Olax haustoria, it is almost invariably 
* Peirce, G. J.,On the Structure of some Phanerogamic Parasites, Annals of Botany, 
Vol. VII, 1893. 
