Edible and poisonous mushrooms of Canada

PARTS OF A MUSHROOM
For the purpose of this book relatively little emphasis is being placed on
microscopic characters but some mention of them must be made in order to
understand the function of the mushroom fruiting body. A mushroom repro-
duces by means of spores and the fruiting bodies are organs developed to
promote the dissemination of the spores.
Spores of very varied forms are produced by fungi in general but in the
mushrooms they usually consist of a single, minute cell, rarely more than 1 /50
milhmeter or 0.0008 inch in length and usually much smaller. They are too
small to be seen singly by the naked eye but in mass appear as a white or
colored powder. Their size, shape, and surface markings, if any, are important
in identifying species but these features can be seen only with the microscope.
The measurements of spores are usually expressed in /x (microns). One m
(micron) equals one one-thousandth of a milhmeter. Thus when we say a spore
is 10m in length we mean 10/1000 or 1 /lOO of a milhmeter in length and since a
milhmeter is about 1 /25 of an inch, it would take 2500 such spores to equal
one inch.
Minute objects such as these are measured by placing a glass disk marked
with a scale in the eyepiece of the microscope. The scale can be carefully cali-
brated with a special slide that is ruled very accurately in tenths and hun-
dredths of a milhmeter. It is then easy to calculate what each division on the
eyepiece scale measures and the spores can be measured directly in ordinary
shde mounts.
20 ^ 21 ^22 "23 '
24
^?
25 26 27 2829 30 31 32 33 34 35 36
Figures 17-24. Semidiagrammatic drawings illustrating some types of cystidia: 17, fusiformlanceolate;
18, flask-shaped; 19, capitate-encrusted; 20, horned; 21, ventricose-fusiform
22, clavate with projections at the apex; 23, cylindric, obtuse with mucronate tip; 24, ninepin-shaped
(lecythiform).
Figures 25-36. Semidiagrammatic drawings illustrating various types of spores: 25, globose;
26, ovoid; 27, ellipsoid; 28, ellipsoid-fusiform; 29, cylindric; 30, allantoid; 31, ellipsoid with
truncate apex; 32, longitudinally striate; 33, angular; 34, tuberculate; 35, reticulate; 36,
echinulate.
;