674 Wisconsin Academy of Sciences, Arts, and Letters. 
I have studied most fully by this method the large eccen¬ 
tric grains of Canna and of potato, which show the orange layer 
most sharply if the starch from rhizomes of growing plants 
of Canna or from ordinary fairly grown potatoes Is studied. 
In the Canna grains, the orange zone extends around the inner 
violet-stained layers as a complete layer, usually fairly uniform 
in thickness (PL XXXIX, Pig. 37), or sometimes somewhat 
broader at the posterior end of the grain (PL XXXVIII, Pig. 
1). Sections cut from any given portion of the rhizome of 
Canna usually contain starch grains which show a certain uni¬ 
formity in staining and differ slightly from those in other re¬ 
gions, but in most cases a peripheral orange layer is present on 
a large proportion of the grains, whether the sections are taken 
from regions nearer to or more remote from the growing point. 
A rhizome of Canna which had lain dormant through the 
winter, but from which a strong shoot was growing at the time 
the preparation was made, showed, almost invariably, starch 
grains with orange-staining peripheral layers. The outer starch 
layers of these grains showed slight corrosion, and no doubt 
these grains were being used for the development of the shoot. 
The small grains, which show their laminae distinctly, show 
this peripheral layer with great uniformity. In certain prepa¬ 
rations, the large grains do not show an orange layer, while the 
smaller grains in the same preparation show the layer dis¬ 
tinctly. 
In other material it was impossible to demonstrate a dif¬ 
ferentiated peripheral layer, either on the large or small 
grains, and it seems fair to assume that these have been in a 
growing condition. 
The starch grains in the stem of Pellionia Daveauana are 
large and of the eccentric type. In the outer part of the cor¬ 
tex, the grains are not so large and are enclosed in relatively 
large chloroplasts (Pl. XXXVIII, Pigs. 17-20). The grains 
nearer the center of the stem are large, and the chloroplasts are 
extended as thin membranes somewhat thicker at the posterior 
side of the grain. When treated with the triple stain, a periph¬ 
eral orange-stained layer is clearly differentiated. The 
