Structure and growth
Mushrooms consist wholly of cells. These cells do not contain either starch or the green coloring-matter, called chlorophyll, which exists in other plants. They are either parasites or scavengers, and sometimes both. The food of fungi must form a part of some animal or plant. When they commence to grow it is by the division of cells, not laterally, but in one direction, upward. As the mushroom grows the stem lengthens, the cap expands and bursts the veil that surrounds it, and gradually gains its perfect shape.
Every mushroom has a spore-bearing layer of cells, which is called the hymenium. This hymenium is composed of a number of swollen, club-shaped cells, called basidia, and close to them, side by side, are sterile, elongated cells, named paraphyses. In the family called Hymenomycetes there are mixed with these, and closely packed together, one-celled sterile structures named cystidia.
The basidia are called mother-cells because they produce the spores.
There is one great group of fungi called Basidiomycetes, so named from having their stalked spores produced on basidia.
The basidia are formed on the end of threadlike branched bodies which grow at the apex, and are called hyphæ. On top of the basidia are minute stalk-like branches, called sterigmata (singular sterigma), and each branch carries a naked spore. They are usually four in number. This group of Basidiomycetes is divided into (1) Stomach fungi (Gasteromycetes), (2) Spore sac fungi (Ascomycetes), and (3) Membrane fungi (Hymenomycetes).
Mycelium
The Mycelium is commonly called the spawn of mushrooms.
It is the vegetative part of the fungus, and is composed of minute, cylindrical, thread-like branching bodies called hyphæ. When we wish to cultivate mushrooms we plant the spawn not the spores. The thread-like branches permeate the earth or whatever the mushroom grows upon. The color of the mycelium is generally white, but it may also be yellow or red. Its structural details are only visible through a microscope.
Every fungus does not bear the spores exposed upon the cap nor underneath it. The first group of Gasteromycetes, or “Stomach fungi,” as Professor Peck has called them in his work on “Mushrooms and Their Uses,” have the spore-bearing surface enclosed in a sac-like envelope in the interior of the plant. The genus Lycoperdon belongs to this group, and it contains the puff-balls so common in this country.
In the second group, Ascomycetes, or “Spore sac fungi,” the spores are produced in delicate sacs called asci. The fruit-bearing part is often cup-shaped, disc-like, or club-shaped, thicker at the top or covered with irregular swellings and depressions like the human brain.
The Morels and Helvellas belong to this group. One often meets with mushrooms of the former genus in the spring, and they are striking and interesting looking fungi. There are many of both genera that are edible. They will be described in detail later.
Botanists have classified Agarics by means of the color of the spores, and it is the only sure way of determining to what class they belong. We propose in this work also to enumerate the mushrooms according to the color of the pileus or cap, and give a list, with a description of each, after this arrangement. This, of course, is merely superficial, but may interest and attract a beginner in the study of fungi. This list will be placed at the end of the book.
The descriptions will be preceded by a classification according to color of spores, some hints to students, and aids to learning which have been found useful to others.
It is appalling to a beginner when he first reads the long list of names of classes, genera, and species, as the latter are so closely allied in resemblance. One has not always the time nor inclination to condense facts for himself, nor to collect necessary information so as to remember it most easily, all which has to be done in the absence of an American manual or textbook. A great deal has been written for us, it is true, by experienced botanists, but a general and comprehensive work has yet to be compiled.
Before we begin our list of fungi, let us learn what a mushroom is, and know something of its component parts. A mushroom consists of a stem and a cap, or pileus. The cap is the most conspicuous part. The color varies from white and the lightest hues of brown up to the brightest yellow and scarlet. Its size is from an eighth of an inch to sixteen inches and more in diameter. The surface is smooth or covered with little grains (granular) or with minute scales (squamulose) shining like satin, or kid-like in its texture. It may be rounded and depressed (concave), elevated (convex), level (plane), or with a little mound in the centre (umbonate). It may be covered with warts, marked with lines (striate), or zoned with circles. The margin may be acute or obtuse, rolled backward or upward (revolute), or rolled inward (involute); it may be thick or thin.
The Stem
The stem is the stalk that supports the cap. It is sometimes attached to one side, and then it is said to be lateral or between the centre and side, and it is called eccentric; when it is in the middle, or nearly so, it is central.
It is either solid, fleshy, stuffed with pith, or hollow, fibrous, firm and tough (cartilaginous). It is often brittle and breaks easily, or it will not divide evenly in breaking. Its color and size both vary, like the cap. It may taper toward the base, or toward the apex, be even or cylindrical. Its surface may be smooth (glabrous), covered with scales (squamulose), rough (scabrous), dotted, lacerated, or be marked with a network of veins (reticulated). The base may be bulbous, or only swollen (incrassated), and it may root in the ground.
The Gills
The gills or lamellæ are the radiating parts, like knife blades, that extend from the centre to the margin underneath the cap. They contain the spores. The group of mushrooms that have gills are called Agaracini or Agarics. The gills vary in color; sometimes they change color when mature. When they are close together they are called crowded, and when far apart distant. There are often smaller gills between the others, and sometimes they are two-forked (bifurcate), and are connected by veins.
They are narrow or wide, swell out in the middle (ventricose), are curved like a bow (arcuate), and have a sudden wave or sinus in the edge near the stem (sinuate).
There are various modes of attachment to the stem. Where the gills are not attached to it they are called free; slightly so, adnexed; and when wholly fastened they are adnate. They may run down on the stem, and are then called decurrent.
The Spores
The color of the spores can be seen by cutting off the cap, and laying it gills downward, on a sheet of paper, two or three hours or more. The impression will remain on the paper. It is better to use blue paper, so that the white spores can be seen more clearly. The Agarics are divided into classes according to the color of the spores, so it is of great importance to examine them. The shape and size of the spores can only be learned by the use of a microscope. We have not attempted in this elementary work to do more than mention them.
The Volva and Veil
The universal veil or volva is a thin covering which encloses the entire young plant. The cap grows and expands and bursts this veil into fragments. That part of the veil which breaks away from the cap, called the secondary veil, forms the annulus or ring. It resembles a collar, and is generally fastened to the stem. It is not always permanent or fixed in one place. It may disappear when the plant is mature. It is often fragile, loose and torn, and sometimes is movable on the stem.
The name volva is particularly given to that part of the universal veil which remains around the base of the stem, either sheathing it or appressed closely to it, or in torn fragments. The volva and ring, or annulus, are not always present in mushrooms. The rupture of the veil often causes a part of it to remain on the cap in the shape of warts or scales. These may disappear as the plant grows older, and are sometimes washed off by a heavy rain.
The Tubes or Pores
There is a group of fungi called Polyporei, which have tubes or pores instead of gills. They are placed under the pileus just as the gills are situated, and contain the spores. The length of the tubes varies. The mouths or openings are also of different shapes and sizes. They are sometimes round, and at other times irregular. The color of the mouths is often different from the tubes, and changes when mature. The mouths, too, are sometimes stuffed when young. The attachment to the pileus is to be noted. They may be free or easily detached, depressed around the stem or fastened to it (adnate.)
1. Worcester’s Dictionary, citing Brande.