_Tube mushrooms_
The structure of these mushrooms is clearly shown in Plate 38, in my
chapter on "Spore-prints," the hymenium being here spread upon the
honey-combed pore surfaces, and shedding its spores from the tubes.
Each of these tubes is distinct and may be separated from the mass.
The ideal form as shown in Plate 20 is perfectly symmetrical, in
which condition the pores would naturally be perpendicular. But this
perfection seldom prevails, and we continually find the specimens
more or less eccentric in shape, especially where they are crowded or
have met with obstruction in growth. But in any case, no matter what
the angle or distortion of growth during development, the _tubes_ are
always adjusted to the perpendicular, or in malformed individuals as
nearly so as the conditions will permit, as shown in the section on
next page.
The Boleti are in general a salubrious group. Certain species have
long been accredited as being poisonous, and others excluded from the
feast as "suspicious." The early authorities caution us to avoid all
Boleti having any shade of red on the spore-bearing surface beneath,
even as it was originally claimed that all _red-capped_ toadstools were
poisonous. But from the writer's own individual experiments, reinforced
by the experience of others, he is beginning to be persuaded that the
Boletus as a _genus_ has been maligned. Many species accredited as
poisonous he has eaten repeatedly without the slightest deleterious
consequences, including the crimson Boletus, _B. alveolatus_ (Plate 24,
fig. 2), with its red spore surface, and the _B. subtomentosus_ (Plate
22, fig. 1), whose yellowish flesh, like the species just mentioned,
changes quickly to blue upon fracture, a chemical feature which has
long stamped both species as dangerous.
[Illustration: SECTION OF BOLETUS SHOWING PERPENDICULAR TUBES]
[Sidenote: =Maligned species=]
It is interesting to note that the ban is gradually being lifted from
the Boleti by mycophagists of distinction, largely through their own
experiments. Thus I note that Mr. McIlvaine, who has made a close study
of esculent fungi, in a recent article claims that "all the Boleti
are harmless, though some are too bitter to eat"; and Mr. Palmer, in
his admirable portfolio of esculent fungi, includes among his edible
species one of those whose flesh "changes color on fracture," and which
has hitherto been proscribed as "off color." Of course, this food
selection would obviously apply only to species of inviting attributes,
possessing pleasant odor, agreeable taste, and delicate fibre. The
selection comprised in this volume is confined to a few varieties of
established good repute. As to the rest--if only on the consideration
of idiosyncrasy--it is wiser to urge extreme caution on the lines laid
down on page 34.
[Sidenote: =Changes of form in growth=]
The Boletus, like all other mushrooms, passes through a variety of
forms from its birth to maturity, at first being almost round, then
convex, with the spore surface nearly flat, horizontal, the profile
outline finally almost equally cushion-like on both upper and lower
surfaces, or the upper surface absolutely flat. Mere outline drawings
of a number of Boleti would be almost identical. The form alone,
therefore, is of minor importance in their identification. Among those
more readily recognized by their color and structural features, may be
classed the following common species:
[Illustration: _Boletus edulis_]
_PLATE XX_