Materials in Evergreen Herbaceous Leaves . 205 
winter (Fig. 3). It has been observed that the starch grains are grouped as 
though each group had arisen from a single oil globule. 
No regular variation in the conversion has been determined. Entire 
plants have been tested, and it has been shown that they do not possess 6 fat * 
leaves and ‘ starch 1 leaves — all leaves tend to form starch when exposed to 
higher temperature. Fig. 4 shows the test of three plants from material 
which had been exposed to higher temperature for four days. 
In this test, plants I and III gave a strong reaction in all of the 
leaves, but very little reaction was obtained in any leaves from plant II. 
Fig. 3. Horizontal section of Linnaea leaf, showing oils and fats in epidermal cells. Material fresh 
from outside before exposure to higher temperature. Section treated with i per cent, osmic acid. 
Fig. 4. Linnaea material exposed to higher temperature for four days, sections of which were 
treated with chloral hydrate and iodine. 
Strong starch reaction in sections from a x -a r -b x -b 2 -c 2 , g x -g-2-h x -h 2 -i x -i 2 . 
Slight starch reaction in sections from e x -f T 
No „ ,, „ ,, ,, e 2 -d x -d 2 . 
This may be due to the fact that its leaves were not so vigorous as those . of 
plants 1 and in. Hence any variation seems to be due to some plants being 
more vigorous than others, and also to the age of the leaves, as it has been 
observed that younger leaves carry on the conversion much more rapidly 
than do the older ones. 
