MINUTE STRUCTURE OF LEAVES 18535, 
Notice that the green coloring matter is not uniformly 
distributed, but that it is collected into little particles 
called chlorophyll bodies (Fig. 120, p). 
166. Woody Tissue in Leaves. — The veins of leaves 
consist of fibro-vascular bundles containing wood and 
vessels much like those of the stem 
of the plant. Indeed, these bundles 
in the leaf are continuous with those 
of the stem, and consist merely of 
portions of the latter, looking eats ‘i 
as if unraveled, which pass 
outward and upward from the 
stem into the leaf under 
the name of leaf-traces. ¢ 
These traverse the peti-& , 
ole often in a somewhat 
irregular fashion. 
iW ge 
pi 
. 
1 
ar 
il 
Fic. 120. — Termination 
: of a Vein in a Leaf. 
EXPERIMENT XXVUI (Magnified ie ode 
Passage of Water from pic gewed 
Stem to Leaf.—Place a id peer Ace opine cer 
freshly cut leafy shoot of some Chyma-cells of the 
J 5 spongy interior of the 
plant with large thin leaves, leaf, with chlorophyll 
such as Hydrangea hortensia, eg haere 
in eosin solution for a few 
minutes. As soon as the leaves show a decided reddening, pull 
some of them off and sketch the red stains on the scars thus made. 
What does this show? 
167. Experimental Study of Functions of Leaves. — The 
most interesting and profitable way in which to find out 
what work leaves do for the plant is by experimenting 
upon them. Much that relates to the uses of leaves is 
