as enemies of the
forest, they are, at the same time, of incalculable use to the forest.
The mushrooms are nature's most active agents in the disposal of the
forest's waste material. Forests that have developed without the
guidance of man have been absolutely dependent upon them for their
continued existence. Where the species of mushrooms are comparatively
few which attack living trees, there are hundreds of kinds ready to
strike into fallen timber. There is a degree of moisture present on the
forest floor exactly suited to the rapid growth of the mycelium of
numbers of species in the bark, sap wood, and heart wood of the fallen
trees or shrubs. In a few years the branches begin to crumble because of
the disorganizing effect of the mycelium in the wood. Other species
adapted to growing in rotting wood follow and bring about, in a few
years, the complete disintegration of the wood. It gradually passes into
the soil of the forest floor, and is made available food for the living
trees. How often one notices that seedling trees and shrubs start more
abundantly on rotting logs.

The fallen leaves, too, are seized upon by the mycelium of a great
variety of mushrooms. It is through the action of the mycelium of
mushrooms of every kind that the fallen forest leaves, as well as the
trunks and branches, are converted into food for the living trees. The
fungi, are, therefore, one of the most important agents in providing
available food for the virgin forest.

The spawn of some fungi in the forest goes so far, in a number of cases,
as to completely envelop those portions of the roots of certain trees as
to prevent the possibility of the roots taking up food material and
moisture on their own account. In such cases, the oaks, beeches,
hornbeams, and the like, have the younger parts of their roots
completely enveloped with a dense coat of mycelium. The mycelium in
these cases absorbs the moisture from the soil or forest floor and
conveys it over to the roots of the tree, and in this way supplies them
with both food and water from the decaying humus, the oak being thus
dependent on the mycelium. In the fields, however, where there is not
the abundance of humus and decaying leaves present in the forest, the
coating of mycelium on the roots of these trees is absent, and in this
latter case the young roots are provided with root hairs which take up
the moisture and food substances from the soil in the ordinary way.

The mushrooms al