62 Bunting—The Structure of the Cork Tissues in 
Pyrus Malus, Pyrus communis and Eriobotrya nuclei were not 
demonstrated. In these species the cork cells were very 
small and surrounded by heavy cell walls, hence it was 
difficult to prepare sections, and thus reach definite conclusions 
as to the presence of nuclei. 
(2) Starch in the Cork Region.—In making tests for cork, by 
the use of iodine and sulphuric acid, it was observed that 
starch was present in the cork region, hence iodine was used 
with the different Rosaceous species in order to determine in 
what species starch was present in the roots. As a result of 
this test, starch was found in all the Rosaceous roots. Among 
the herbaceous and shrubby species it is observed in large 
quantities ; though a relatively larger amount is found in the 
younger layers of cells toward the cork cambium, than in the 
uniseriate flattened cells with pigment contents, or in the cells 
which are peeling off, although it may be found in all of 
these. In Prunus virginiana, Pyrus Malus, P. communis and 
Eviobotrya japonica starch is also found in the cork cells, 
although in the roots of these species the quantity is not so 
great as in herbaceous roots. As would be expected, the 
amount of starch varies with the time of year in which the 
roots are studied. In late autumn, winter and early spring the 
periderm cells are loaded with starch, while the amount is 
appreciably decreased in the late spring and summer. This 
fact seems to indicate that the starch is used by the root, and 
that the cork cells as well as the other cells are reservoirs in 
which it can be stored. It would be very desirable to make 
tests for sugar, when the growth of the root has commenced, 
in order to determine definitely whether the starch found in 
this region is a reserve or a waste product. 
(ce) Pigment of the Cork Region.—Many of the genera of 
Rosaceeé contain pigment in some or all of the cells, as well 
as in the cell walls, it is however most frequently found in the 
uniseriate flattened layer, where such an annular layer is 
present. In sections of Pyrus Malus all the cells contained a 
