178 THE ESSEX NATURALIST.
At each autumn foray the destructive character of the white
slimy agaric, Armillaria mucida, is apparent among the beeches,
trees, formerly magnificent, in the grip of the fungus, affording
striking examples of the destructive work that is always in pro-
gress. This fungus, as it appears in its sporophore stage, is
always attractive on account of its pure white colour, and
it excites more than a passing interest when it is realised
as being the cause of the destruction of much valuable timber
and as rendering less attractive the sylvan beauty of the
beech wood by leaving the slain giants of the forest strewn
upon the ground.
Another widely known tree-destroying agaric is the honey
fungus, Armillaria mellea, which attacks, in the first place, the
roots of trees and does great damage to both root and trunk
before the true nature of the attack is suspected. The spore-
bearing toad-stools of this parasite appear at the base of the
infected tree. It has been stated that more trees die in Europe
from attack by this fungus than by any other parasitic agent.
The whole progress from infection to the resulting death is an
interesting story. The result of the attachment of this fungus
to the tuber of an orchid Gastroidea, widely distributed in
Japan, is perhaps of greater interest as a case of romance in
plant life: indeed it is not until the hyphae of the fungus
pierce the cells of the tuber that the orchid is stimulated into
flowering.
Other fungi, that are among those most frequently exhibited
after a foray, are the fly agaric, Amanita muscaria, Boletus scaber,
and the common earth-ball, Scleroderma vulgare. Mycelial
threads of these fungi attach themselves to the smallest of the
root-branches of forest trees, but the attachment is by means
of a thread so fine that the actual connecting point between
the spore-bearing portion, which is formed above ground and
the slender root, is not often easy to demonstrate. The sporo-
phore may be several inches from the rootlet; mycelial threads
can be very easily broken, and lost sight of entirely, in removing
the decaying leaves and soil through which they pass. When
the mycelial threads reach the rootlets they completely sur-
round them and by growth and much branching cover them
with a mantle, so closely woven in certain forms, that threads
lose their individuality and resemble in section a parenchymatous