The boletes of Michigan, by Alexander H. Smith and Harry D. Thiers.

2

THE BOLETES OF MICHIGAN

distinct ring of tissue on the stipe the ring is called an annulus. Often,
however, the remains of the veil adhere to the margin of the pileus, and
the margin is then said to be appendiculate or the margin itself may
project as a thin membrane which finally becomes divided into segments. The tissue of the veil may be soft and cottony, membranous, or
slimy. If slimy, very often the pileus surface is slimy also, and when
such a surface dries it frequently has the appearance of having been
varnished.
It will be noted that the tubes of a bolete are nearly always
arranged vertically even if the stipe must curve to accomplish this. The
vertical alignment enables the spores, when they are shot off from the
basidia (for a short distance), to fall the length of the tube without
being caught by the basidia or spores below. The spores, or most of
them, fall free of the tubes and are carried away by air currents to new
habitats which, if favorable, will serve as new locations for the fungous
plant. Many spores, of the millions produced, fall in unfavorable localities and either do not germinate or, if they do, the young fungous plant
soon dies.
The spores (figs. 24) apparently may rest in the soil for a fairly
long time without starting to grow. Growth begins, we presume, when a
bubble of protoplasm exudes through an opening in the spore wall and,
later, filaments grow out of the bubble. Spores of boletes are very
difficult to germinate.
Spores have rather distinctive shapes and markings in many species
(figs. 22, 47, 113), and since these features are constant for a species
the differences are very important in bolete classification. Spores can be
collected easily by cutting off the stipe of a basidiocarp at the level of
the tubes, standing the pileus on a piece of white paper with the tubes
down but supported so as to keep them from touching the paper, and
covering the setup with a container of some sort to cut off air currents.
If the basidia are producing and discharging spores, in an hour or two
the accumulation of colored spore dust will be noted under the hymenophore. The color of this "spore deposit" is important in classifying
boletes. Excess moisture should be allowed to evaporate before a final
notation is made as to the color of the deposit.
With this much of an introduction to the bolete basidiocarp, we
now consider the plant which produces it. Some of us still regard fungi
as plants, albeit they are a rather special type. The bolete plant is a mass
of threads (spawn), in the main much like the spawn of the mushroom.
Technically, we designate both as mycelium. The threads making up the
mycelium are branched and, depending on the species, vary from 2 to