ECONOMIC RELATIONS OF FUNGI.
some species its growth is not uniform, and the stalk is excentric, or even lateral. Lastly, let it be remembered that the toadstool which we The economic relations of the fungi are of great importance. Some are edible and furnish wholesome food to man and other animals, some are used in the arts, some yield medicines, some are the cause of disease in man and other animals, and some again attack and destroy other plants, including many of the cultivated plants of our farms and gardens.
Edible Here perhaps we should include those bacteria which have to do with the flavor of butter and cheese, and those molds whose presence in cheese adds to its edibility. Of far greater importance, however, are those species which are eaten for the nutriment which they contain. Truffles are collected in Europe, and sold in the markets. Dogs and pigs are trained to search for them, the attendant bagging the truffle when found by the keen scent of the animal. The Morels are sac fungi related closely to the cup fungi; each Morel (fruit) is a hollow-stalked body two to five inches high, with a crinkled and pitted conical cap in whose surface are embedded the spore sacs. They grow in fields and in thickets, and when fresh are wholesome. Morels are often called mushrooms, although this name should be restricted to the next group.
Mushrooms (Fig. 29) are of the toadstool kind, and popularly but incorrectly any species which is edible is called a mushroom, while those which are poisonous are called toad stools. Many species are collected from the forests and fields by experts who have learned to distinguish them from the poisonous ones, but by far the most commonly used species is the common mushroom (Agaricus conspestris) which is cultivated by gardeners for this pur pose. See MUSHROOMS.
Poisonous Fungi.— Although the vast ma jority of the toadstools and other fleshy fruited fungi are edible or innocuous there are a num ber that are extremely poisonous and many others that, while not deadly, yet are likely to cause great discomfort or nausea. The most
dangerous are the Death-cup (Amanita phal loules) and the Fly Mushroom (Amanita muscaria). The Emetic Russula (Russula ense tica) is a common fungus that is poisonous, but its emetic nature prevents any serious in jury. The occurrence of poisonous species of mushrooms makes great caution necessary on the part of those who otherwise would have in the great supply of mushrooms in the late sum mer and fall a source of food to be had for the picking. The only safe rule is to avoid any mushroom unless it is known to be harmless.
Medicinal Fungi.— The most important species is the Ergot (Spermcedia clavus), one of the sac fungi, which is parasitic in the heads of rye.
Pathogenic Fungi (on Animals).— Many bacteria are the direct cause of diseases of ani mals, including man. See BACTERIA.
Some of the water molds cause a serious disease of fishes, especially of young fishes in 'hatcheries.* Occasionally an epidemic, known as the °Salmon Disease," has been known to occur in the streams of Great Britain. Investi gation has shown it to be due to a certain species of water mold.
The insect fungi (Entomophthoraccce) annu ally destroy immense numbers of flies, locusts, caterpillar larvae, etc. The common house fly is attacked by Entomophthora muscce in sum mer and autumn. Every infected insect fastens itself by means of its tongue to some object, and soon perishes miserably, its body walls being pierced by innumerable spore-hearing branches. In the autumn myriads of locusts are destroyed by Entomoph thora grylli. When attacked by the fungus the locust climbs a grass or weed stem around which it finally clasps its legs and dies firmly attached. Many other insects, including mos quitoes, are destroyed by these beneficial fungi. Thus far all attempts to artificially apply these fungi in combating insects have been unsuccess ful.
Several species of Aspergillus and other genera bring about a serious disease of the ear Passages in man.
Pathogenic Fungi (on Plants). See