Lesson CLXXIX

Mushrooms

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 , , , 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.

Observations—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?