Mushrooms and Other Fungi
HERE is something uncanny about plants which have no green parts; they seem like people without blood. It is, therefore, no wonder that many superstitions cluster about toadstools. In times of old, not only did the toads sit on them, but fairies danced upon them and used them for umbrellas. The poisonous qualities of some species made them also a natural ingredient of the witch's cauldron. But science, in these days, brings revelations concerning these mysterious plants which are far more wonderful than the web which superstition wove about them in days of yore.
When we find plants with no green parts which grow and thrive, though unable to manufacture their own organic food through the alchemy of chlorophyl, sunlight and air, we may safely infer that in one way or another they gain the products of this alchemy at second hand. Such plants are either parasites or saprophytes; if parasites, they steal the food from the cells of living plants; if saprophytes, they live on such of this food material as remains in dead wood, withered leaves, or soils enriched by their remains.
Thus, we find mushrooms and other fungus fruiting bodies, pallid, brown-olive, yellow or red in color, but with no signs of the living green of other plants; and this fact reveals their history. Some of them are parasites, as certain species of bracket fungi which are the deadly enemies of living trees; but most of the fungus species that we ordinarily see are saprophytes, and live on dead vegetation. Fungi, as a whole, are a great boon to the world. Without them our forests would be choked out with dead wood. Decay is simply the process by which fungi and other organisms break down dead material, so that the major part of it returns to the air in gaseous form, and the remainder, now mostly humus, mingles with the soil.
As a table delicacy, mushrooms are highly prized. A very large number of species are edible. But every year the newspapers report deaths resulting from eating the poisonous kinds—the price of an ignorance which comes from a lack of the powers of observation developed in nature-study. It would be very unwise for any teacher to give rules to guide her pupils in separating edible from poisonous mushrooms, since the most careful directions may be disregarded or misunderstood. She should emphasize the danger incurred by mistaking a poisonous for an edible species. One small button of the deadly kind, if eaten, may cause death. A few warning rules may be given, which if firmly impressed on the pupils, may result in saving human life.
First and most important, avoid all mushrooms that are covered with scales, or that have the base of the stem included in a sac, for two of the poisonous species, often mistaken for the common edible mushroom, have these distinguishing characters. Care should be taken that every specimen be collected in a way to show the base of the stem, since in some poisonous species this sac is hidden beneath the soil.
Second, avoid the young, or button, stages, since they are similar in appearance in species that are edible and in those that are poisonous.
Third, avoid those that have milky juices; unless the juices are reddish in color, the mushrooms should not be eaten.
Fourth, avoid those with shiny, thin, or brightly colored caps, and those with whitish or clay-colored spores.
Fifth, no mushroom or puffball should be eaten after its meat has begun to turn brown or has become infested with fly larvæ.
How Mushrooms Look and How They Live
HERE are many kinds of mushrooms varying greatly in form, color and size, but wherever they appear it means that sometime previous the mushroom spores have been planted there. There they threw out threads which have penetrated the food substance and gained a successful growth, which finally resulted in sending up into the world the fruiting organs. In general shape these consist of a stem with a cap upon it, making it usually somewhat umbrella-shaped. Attached to the cap, and usually under it, are plate-like growths called gills, or a fleshy surface which is full of pores. In the case of the gills, each side of each plate develops spores. These, as fine as dust, are capable of producing other mushrooms.
In the common edible species of mushroom (Agaricus campestris), the stem is white and almost cylindrical, tapering slightly toward the base; it is solid although the core is not so firm as the outside. When it first pushes above the ground, it is in what is called the "button stage" and consists of a little, rounded cap covered with a membrane which is attached to the stem. Later the cap spreads wide, for it is naturally umbrella-shaped, and it tears loose this membrane, leaving a piece of it attached to the stem; this remnant is called the ring or collar. The collar is very noticeable in many species, but in the common mushroom it soon shrivels and disappears. The cap is at first rounded and then convex; its surface is at first smooth, looking soft and silky; but as the plant becomes old, it is often broken up into triangular scales which are often dark brown; although the color of the cap is usually white or pale brown. The gills beneath the cap are at first white, but later, as the spores mature, they become brownish black because of the ripened spores.
References—Mushrooms, a most excellent and practical book with many beautiful pictures, written and illustrated by Professor George F. Atkinson; Henry Holt & Co., N. Y., $3.00; The Mushroom Book, Marshall, fully illustrated, $4.00, Doubleday, Page & Co.; One Thousand American Fungi, McIlvaine, illustrated, Bowen-Merrill Co., $5.00; Our Edible Toadstools and Mushrooms, W. H. Gibson, very fully illustrated, Harper and Bros., $3.50.
Leading thought—Mushrooms are the fruiting organs of the fungi which grow in the form of threads, spreading in every direction through the food material. The dust which falls from ripe mushrooms is made up of spores which are not true seeds, but which will start a new growth of the fungus.
Method—The ideal method would be to study the mushrooms in the field and forest, making an excursion for the purpose of collecting as many species as possible. But the lesson may be given from specimens brought into the schoolroom by pupils, care being taken to bring with them the soil, dead wood or leaves on which they were found growing. After studying one species thus, encourage the pupils to bring in as many others as possible. There are a few terms which the pupils should learn to use, and the best method of teaching them is to place the diagrams shown on pages 708, 711, 712, on the blackboard, and leave them there for a time.
Since mushrooms are especially good subjects for water-color and pencil studies, it would add much to the interest of the work if each pupil, or the school as a whole, should make a portfolio of sketches of all the species found. With each drawing there should be made on a supplementary sheet a spore-print of the species. White paper should be covered very thinly with white of egg or mucilage, so as to hold fast the discharged spores when making these prints for portfolio or herbarium.
1. Where was the mushroom found? If on the ground, was the soil wet or dry? Was it in open fields or in woods? Or was it found on rotten wood, fallen leaves, old trees or stumps, or roots? Were there many or few specimens?
2. Is the cap cone-shaped, bell-shaped, convex, plane, concave, or funnel-form? Has it a raised point at the center? How wide is it?
3. What is the color of the upper surface of the cap when young? When old? Has it any spots of different colors on it? Has it any striate markings, dots or fine grains on its surface? Is its texture smooth or scaly? Is its surface dull, or polished, or slimy? Break the cap and note the color of the juice. Is it milky?
4. Look beneath the cap. Is the under surface divided into plates like the leaves of a book, or is it porous?
5. The plates which may be compared to the leaves of a book are called gills, although they are not for the purpose of breathing, as are the gills of a fish. Are there more gills near the edge of the cap than near the stem? How does this occur? What are the colors of the gills? Are the gills the same color when young as when old? Are the lower edges of the gills sharp, blunt or saw-toothed?
6. Break off a cap and note the relation of the gills to the stem. If they do not join the stem at all they are termed "free." If they end by being joined to the stem, they are called "adnate" or "adnexed." If they extend down the stem they are called "decurrent."
7. Take a freshly opened mushroom, cut off the stem, even with the cap, and set the cap, gills down, on white paper; cover with a tumbler, or other dish to exclude draught; leave it for twenty-four hours and then remove the cover, lift the cap carefully and examine the paper. What color is the imprint? What is its shape? Touch it gently with a pencil and see what makes the imprint. Can you tell by the pattern where this fine dust came from? Examine the dust with a lens. This dust is made up of mushroom spores, which are not true seeds, but which do for mushrooms what seeds do for plants. How do you think the spores are scattered? Do you know that one little grain of this spore dust would start a new growth of mushrooms?
8. Look at the stem. What is its length? Its color? Is it slender or stocky? Is its surface shiny, smooth, scaly, striate or dotted? Has it a collar or ring around it near the top? What is the appearance of this ring? Is it fastened to the stem, or will it slide up and down? Is the stem solid or hollow? Is it swollen at its base? Is its base set in a sac or cup, or is it covered with a membrane which scales off? Do you know that the most poisonous of mushrooms have the sac or the scaly covering at the base of the stem?
9. Examine with a lens the material on which the mushroom was growing; do you see any threads in it that look like mold? Find if you can what these threads do for the mushroom. If you were to go into the mushroom business what would you buy to start your beds? What is mushroom "spawn?"
10. If you can find where the common edible mushrooms grow plentifully, or if you know of any place where they are grown for the market, get some of the young mushrooms when they are not larger than a pea and others that are larger and older. These young mushrooms are called "buttons." Find by your own investigation the relation between the buttons and the threads. Can you see the gills in the button? Why? What becomes of the veil over the gills as the mushrooms grow large?
11. Do you know the difference between mushrooms and toadstools? Do you know the common edible mushroom when you see it? What characters separate this from the poisonous species? What is the "death cup," as it is called, which covers the base of the stem of the most common poisonous species?