240 THE ESSEX NATURALIST
whilst the sporophores are mostly very ephemeral structures
usually with lives to be reckoned in days.
There are also in the beechwood fungi with macroscopic
fruit-bodies which never appear above the ground. These
are the hypogeal fungi—the truffles and their like. Most
naturalists, even most mycologists, have tended to regard
them as rather rare. Nevertheless, they seem to be
abundant, but are to be seen only by those who bother to
rake for them. In the early days—the days before the
British Mycological Society—Dr. Broome, a worthy of the
Woolhope Naturalists' Field Club, raked and found many
hypogeal fungi. In recent years, Dr. L. E. Hawker, of
Bristol, has followed in his footsteps and has added con-
siderably to our knowledge of these interesting fungi. The
hypogeal fungi represent a biological group and not a
systematic one, for they comprise Phyeomycetes (e.g.,
Mycogone spp.), Ascomycetes (e.g., Tuber spp. and
Elaphomyces spp.) and Basidiomycetes (e.g., Hymenogaster
spp.). The true truffles belong to the genus Tuber. The
largest British species, and the only native truffle prized
by the mycophagist, is T. aestivum, a single specimen of
which may weigh several ounces, but most British species
are much smaller, often being about the size of a small hazel
nut. As part of my own garden at Otford on the North
Downs, I have a small section of hanger beechwood with
yew undergrowth. Baking in this, I have found two species
of truffle : T. excavatum and T. rufum, as well as a hypogeal
basidiomycete, Hymenogaster luteus. It is generally thought
that these hypogeal fungi form mycorrhiza with the trees.
Apart from the hypogeal fungi, there is a considerable
flora of saprophytic microfungi in the soil of a beechwood
utilising the organic debris incorporated in the soil. We
know little about this flora since, although soil fungi
have attracted considerable attention in recent years, most
of the work has been concerned with agricultural soils
because of their economic importance.
In this brief sketch of fungi and beech I have referred
to only a few species. A complete fungal list for a beech-
wood, including all the parasites and saprophytes of the
tree, all the mycorrhizal species and litter-decomposing
fungi, all the microfungi of the wood, bark, dead leaves and