101 
If the tips of the roots of the hemlock are examined it will 
be seen that many of them are short, blunt, and club-shaped and 
that the branches are curiously clustered, but beyond this, noth- 
ing can be found to indicate a partnership between these organs 
and moulds. If a thin slice be cut from the tip, however, and 
magnified fifty times under the microscope, it will be found that 
the root is completely enclosed in a felt of hyphae or threads of 
a mould or fungus, and that some of the cells of the root are 
penetrated by them. Great numbers 
of the threads run outward from this 
felt and ramify through the soil thickly 
in ali directions. The decay products 
of the d leaves are conducted 
through them into the felt and into 
the root where they are at the service 
of the tree, and are next led upward 
through its body, serving to build up 
mode ot whe 
Fic. 21. Section of mycorhizal 
rovtof hemlock. The dark 
e 
of the cells in the interior. Fic. 20. Mycorhizal roots of hemlock. 
its new tissues, This service of the fungus is repaid by the 
tree in affording it a place to live, and also by giving back to 
it some of the products derived from the soil which have been 
worked up into a form very suitable for the nourishment of the 
do not reach normal size when deprived of it. The destruction 
of the humus or dead leaves in a forest, therefore, cuts off the 
most important food supply of the trees, and if continued, will 
lead to starvation and the disappearance of the forest. 
Saran H. Harrow. 
