FUNGI AND BEECH
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pyrenomycete Xylaria polymorpha, are responsible for the
rotting of sound wood. This whole question of wood-
destroying fungi is of great economic importance and has
been studied extensively. In this country most of the
fundamental work is due to Cartwright and Findlay at the
Forest Products Research Laboratory at Princes Ris-
borough.
Roughly speaking, there are two kinds of wood-rot
caused by fungi. By far the commonest is white-rot. In
this type the fungus utilises both the lignin and the
cellulose, the lignin tending to go first. Polyporus adustus
and Trametes gibbosa are both white-rot fungi. Daedalea
quercina is a typical brown-rot fungus. This is a very
frequent species on oak stumps, and is only rarely to be
found on beech. In brown-rots the cellulose is utilised, but
the lignin remains untouched.
It is of interest to consider briefly the relationship of the
mycelium to the wood which it penetrates. In most wood-
rot fungi the hyphae usually grow through the wood in a
transverse direction. When the tip of a hypha comes in
contact with the wall of a wood fibre, it dissolves its way
through, probably by enzyme action, producing a charac-
teristic bore-hole. Later the hypha swells on either side
of this hole, so that it appears constricted on passing from
fibre to fibre.
We have seen that on a beech stump a considerable fungus
flora develops. Further, in close proximity, other species
may grow that have an underground attachment to the dead
roots of the stump. Reference has already been made to
sporophores of Honey Fungus, often in great numbers, on
dead stumps, but clusters of fruit-bodies are also to be seen
at varying distances up to a few yards away arising from the
surrounding soil, but these are in contact with the stump
by means of underground rhizomorphs. Again, dense tufts
of Polyporus giganteus, distinguished amongst other large
Polypores by blackening of the flesh following injury, are
often to be seen around beech stumps. The fruit-bodies are
connected by a kind of diffuse sclerotium with the roots.
Collybia radicata (Fig. 1) is a special case. This is common
in beechwoods as solitary sporophores. The stalk is
relatively long and the upper brownish surface of the cap