instance, of the spawn of different Polypori and Spfueria, altered
by growing beneath the bark, free from the influence
of light, in such a way as to form rootlike often anastomosing
bodies, with a dark separable cuticle. Sclerotium, on the contrary,
is formed by the concentration of threads into solid
wartlike bodies or nuggets, entirely devoid of fruit, but which
on occasion give rise to various kinds of Fungi, as Agarics,
Pistillaria, Peziza, etc. In one instance I was enabled, in
company with Mr. Hoffmann, to watch the progress of a thin
slice of the Sclerotium, which is so common in mildewed
onions, when placed in a drop of fluid in an air-tight cell, to
the development from its tissues of a perfect Mucor. In some
cases, the spawn merely collects earthy particles about it till
it forms a large solid mass, which, when placed in proper conditions,
produces fruit, as Polyporus tuberaster, a species commonly
eaten in Italy. I t is obvious that such productions
cannot be admitted into a system,* except so long as their
nature is unknown. I t is however feared that some of the
Fungi which figure under difterent genera amongst Coniomycetes
and Hyphomycetes, are in scarcely a better condition,
though they have this difference, that they do produce a sort
of fruit. Occasionally, under deficiency of light. Fungi possess
a stem only, without any pileus, or only a very imperfect
(Tne; and sometimes, where perfect pilei are produced in
one part, mere stems are formed in another, as if there were
not vigour enough for every demand. This latter is the case
to some extent with Marasmius Rotula (Plate 14, fig. 7), but
it is far more conspicuous in some foreign species, as also
* The best general rule is to admit nothing as a real species of Fungus
which does not bear fruit. I t is possible that such formations as Sclerotium
durum may be due to half-a-dozen, different Fungi. Sclerotium complanatum
and S. scutellatum both give rise to the same species o f P istilla ria . As, however,
some persons may wish to know what species have been described, I shall
give them in an appendix.
in some exotic Polypori. As regards the former case, Len-
tinus lepideus and Polyporus squamosus sometimes produce
little more than stems, and in the latter the stem becomes
so branched as to resemble a stag’s-horn. Agaricus ostrea-
tus also, when grown in a vault, assumes sometimes a most
beautiful appearance, like that of a cauliflower, without any
definite pilei. Sometimes even in the open air the stem
swells above and forms a sort of club, without any pileus.
This is the case iu Agaricus popinalis and the North American
H. abortivus. In some cases, again, the pileus, though developed,
is never perfected, as in a curious form of Lentinus
tigrinus not uncommon iu the United States, where the
whole forms a firm mass, suggesting, with its intricate abortive
gills, some new genus, rather than that to which it really
belongs.
I may mention here that a strange transformation takes
place in a portion of the fruit of Agaricus racemosus. The
stem bears little pilei on its sides, as well as one which is
terminal. This latter has gills like a common Agaric, but
the lateral pilei are spurious, and have the structure of a
Stilbum. A somewhat analogous circumstance takes place
in some species of Ascophora, where the lower vesicles contain
very difterent sporidia from that which is terminal,
though in other respects the difference is not so striking as
in the Agaric just mentioned. Species of Nyctalis, when a ttacked
by Asterophora, become nearly abortive, though there
is still some trace of gills.
The spores of Agarics, though apparently perfect, are
sometimes deficient as to their internal structure, and therefore
abortive; and I have observed the sporidia in Spharia
to become diseased from the conversion of their contents
into a dark solid mass.