ungi of a corky or woody nature, are always sought after
for certain species which they seek in vain elsewhere,[W] and those
who possess herbaria know how destructive certain minute members of
the animal kingdom are to their choicest specimens, against whose
depredations even poison is sometimes unavailing.

Some of the Uredines, as _Trichobasis suaveolens_ and _Coleosporium
sonchi_, are generally accompanied by a little orange larva which
preys upon the fungus; and in the United States Dr. Bolles informs us
that some species of _AEcidium_ are so constantly infested with this
red larva that it is scarcely possible to get a good specimen, or to
keep it from its sworn enemy. Minute _Anguillidae_ revel in tufts of
mould, and fleshy Agarics, as they pass into decay, become colonies of
insect life. Small _Lepidoptera_, belonging to the _Tineina_, appear
to have a liking for such _Polyporei_ as _P. sulfureus_ when it
becomes dry and hard, or _P. squamosus_ when it has attained a similar
condition. _Acari_ and _Psocidae_ attack dried fungi of all kinds, and
speedily reduce them to an unrecognizable powder.

III. What are the influences exerted by fungi on other plants? This is
a broad subject, but withal an important one, since these influences
act indirectly on man as well as on the lower animals. On man,
inasmuch as it interferes with the vegetable portion of his food,
either by checking its production or depreciating its quality. On the
lower animals, since by this means not only is their natural food
deteriorated or diminished, but through it injurious effects are
liable to be produced by the introduction of minute fungi into the
system. These remarks apply mainly to fungi which are parasitic on
living plants. On the other hand, the influence of fungi must not be
lost sight of as the scavengers of nature when dealing with dead and
decaying vegetable matter. Therefore, as in other instances, we have
here also good and bad influences intermingled, so that it cannot be
said that they are wholly evil, or unmixed good.

Wherever we encounter decaying vegetable matter we meet with
fungi, living upon and at the expense of decay, appropriating the
changed elements of previous vegetable life to the support of a new
generation, and hastening disintegration and assimilation with the
soil. No one can have observed the mycelium of fungi at work on old
stumps, twigs, and decayed wood, without being struck with the
rapidity and certai