1902 Encyclopedia > Mushroom


Mushroom. There are few more useful, more easily recognized, or more delicious members of the vegetable kingdom than the common mushroom (Agaricus campestris, L.). It grows in short grass in the temperate regions of all parts of the world. Many edible Fungi depend upon minute and often obscure botanical characters for their determination, and may readily be confounded with worthless or poisonous species, but that is not the case with the Common Mushroom, for, although several other species of Agaricus somewhat closely approach it in form and color, yet the true mushroom, if sound and freshly gathered, may be distinguished from all other Fungi with great ease. It almost invariably grows in rich, open, breezy pastures, in places where the grass is kept short by the grazing of horses, herds, and flocks. Although this plant is popularly termed the "meadow mushroom," it never as a rule grows in meadows. It never grows in wet boggy places, never in woods, or on or about stumps of trees. an exceptional specimen or an uncommon variety may sometimes be seen in the above-mentioned abnormal places, but the best, the true, and common variety of our tables is the produce of short, upland, wind-swept pastures. A true mushroom is never large in size; its cap very seldom exceeds 4, at most 5 inches in diameter. The large examples measuring from 6 to 9 or more inches across the cap belong to Agaricus arvensis (Sch.), called from itslarge size and coarse texture the Horse Mushroom, which grows in meadows and damp shady places, and though generally wholesome is coarse and sometimes indigestible. The mushroom usually grown in gardens or hot-beds, in cellars, sheds, &c., is a distinct variety, known as Agaricus hortensis (Cke.). This is a compact and inferior form of the true mushroom, or it may indeed be a hybrid or even a distinct species.

The parts of a mushroom consist chiefly of stem and cap; the stem is furnished with a clothy ring round its middle, and the cap is furnished underneath with numerous radiating colored gills. In the accompanying illustration (1) represents a section through an infant mushroom, (2) a mature example, and (3) a longitudinal section through a fully-developed mushroom. The cap D, e is fleshy, firm, and white within, never thin and watery; externally it is pale brown, dry, often slightly silky or floccose, never viscid. The cuticle of a mushroom readily away from the flesh beneath, as shown at F. The cap has a narrow dependent margin or frill, as shown at G. and in section at H; this dependent frill originates in the rupture of a delicate continuous wrapper, which in the infancy of the mushroom, entirely wraps the young plant; it is shown in its continuous state at J, and at the moment f rupture at k. The gills underneath the cap L, M, N are at first white, then rose-colored, at length brown-black. A point of great importance is to be noted in the attachment of the gills near the stem at O, P; the gills in the true mushroom are (as shown) usually more or less free from the stem, they never grow boldly against it or run down it; they may sometimes just touch the spot where the stem joins the bottom of the cap, but never more; there is usually a slight channel, as at P. all round the top of stem. When a mushroom is perfectly ripe and the gills are brown-black in color, they throw down a thick dusty deposit of fine brown-black or purple-black spores; it is essential to note the color. The spores on germination make a white felted mat, more or less dense, of mycelium; this, when compacted with dry, half-decomposed dung, is the mushroom spawn of gardeners (see Horticulture, vol. xii. p. 284). The stem is firm, slightly pithy up the middle, but never hollow; it is furnished with a floccose ring near its middle, as illustrated at Q,Q; this ring originates by the rupture of the thin general wrapper k of the infant plant. On being cut or broken the flesh of a true mushroom remains white or nearly so, the flesh of the coarser Horse Mushroom changes to buff or sometimes to dark brown. To summarize the characters of a true mushroom:-it grows only in pastures; it is of small size, dry, and with unchangeable flesh; the cap has a frill; the gills are free from the stem, the spores brown-black or deep purple-black in color, and the stem solid or slightly pithy. When all these characters are taken together no other mushroom-like fungus-and nearly a thousand species grow in Britain-can be confounded with it.

Like all widely-spread and much-cultivated plants, the edible mushroom has numerous varieties, and it differs in different places and under different modes of culture in much the same way as our kitchen-garden plants differ from the type they have been derived from, and from each other. In some instances thee differences are so marked that they have led some botanists to regard as distinct species many forms usually esteemed by other as varieties only.

A small variety of the common mushroom found in pastures has been named A. pratensis (Vitt.); it differs from the type in having a pale reddish-brown scaly top, and the flesh on being cut or broken changes to pale rose-color. A variety still more marked, with a darker brown cap and the flesh, changing to a deeper rose, and sometimes blood-red, has been described as A. rufescens (Berk.). The well-known compact variety of mushroom-growers, with its white cap and dull purlish clay-coloredgills is a. hortensis (Oke.) two sub-varieties of this have been described under the names of a. Buchananiand A. elongates, and other distinct forms are known to botanists. A variety also grown in woods named a. silvicola (Vitt.); this can only distinguished from the Pasture Mushroom by its elongated bulbous stem and its externally smooth cap. There is also a fungus well known to botanists and cultivators which appears to be intermediate between the pasture variety and the wood variety, named A. vaporarius (Otto). The large rank Horse Mushroom, now generally referred to as A. arvensis (Sch.), is probably a variety of the Pasture Mushroom; Sowerby has described it under the name of A. georgii and Dr Badham as A. exquisitus; it has also been published as A. edulis. It grows in rings in woody places and under trees and hedges in meadows; it has a large scaly round cap, and the flesh quickly changes to buff or brown when cut or broken; the stem too is follow. An unusually scaly form of this has been described as A. villaticus and another as A. augustus. Dr Badham has alsodescribeda variety under the name of A. anceps.

A species, described by Berkeley and Broome as distinct from both the Pasture Mushroom and Horse Mushroom, has been published under the name of A. elvensis. This grows under oaks, in clusters,- a most unusual character for the mushroom. The species is said to be excellent for the table. An allied fungus peculiar to woods, with a less fleshy cap than the true mushroom, with hollow stem, and strong odor, has been described as a close ally of the Pasture Mushroom under the name of A. silvaticus (Sch.); its qualities for the table have not been described.

Many instances are on record of symptoms of poisoning, and even death, having followed the consumption of plants which have passed as true mushrooms; these cases have probably arisen from the examples consumed being in a state of decay, or from some mistake as to the species eaten. It should always he specially noted whether the fungi to be consumed are in a fresh and wholesome condition, otherwise they act as a poison in precisely the same way as does any other semi-putrid vegetable or putrid meat. Many instances are on record where mushroom-beds have been invaded by a growth of strange fungi and the true mushrooms have been ousted to the advantage of the new-comers; such instances are very perplexing, but they tend to show that a proper supervision should be kept over fungi when used for food as over other vegetables, fruit, meat, and fish. When mushrooms are gathered for sale by persons unacquainted with the different species mistakes are of frequent occurrence. A very common spurious mushroom in markets is A. velutinus (P.), a slender, ringless, hollow-stemmed, black-gilled fungus, common in gardens and about dung and stumps; it is about the size of a mushroom, but thinner in all its parts and far more brittle; it has a black hairy fringe hanging round the edge of the cap when fresh. Another spurious mushroom, and equally common in dealers’ baskets, is A. lacrymabundus (Fr.); this grows in the same positions as the last, and is somewhat fleshier and more like a true mushroom; it has a hollow stem and a slight ring, the gills are black-brown mottled and generally studded with tear-like drops of moisture. In both these species the gills distinctly touch and grow on to the stem. Besides these there are numerous other black-gilled species which find a place in baskets,-some species far too small to bear any resemblance to a mushroom, others large and deliquescent, generally belonging to the stump-and dung borne genus Coprinus. The true mushroom itself is to a great extent a dung-borne species, therefore mushroom-beds are always liable to an invasion from other dung-borne forms. The spores of all fungi are constantly floating about in the air, and when the spores of dung-infesting species alight on a mushroom-bed they find a nidus already prepared that exactly suits them; and if the spawn of the new-comer becomes more profuse than that of the mushroom the stranger takes up his position at the expense f the mushroom. There is also a fungus named Xylaria vaporaria (B.), which some times fixes itself on mushroom-beds and produces such an enormous quantity of string-spawn that the entire destruction of the bed results. The spawn is sometimes to profuse that it is pulled out of the beds in enormous masses and carted away in barrows.

Sometimes cases of poisoning follow the consumption of what have really appeared to gardeners to be true bed-mushrooms, and to country folks as small Horse Mushrooms. The case is made more complicated by the fact that these highly-poisonous forms now and then appear upon mushroom-beds to the exclusion of the mushrooms. This dangerous counterfeit is A. fastibilis (Fr.), or sometimes A. crustuliniformis (Bull.), a close ally if not indeed a mere variety of the first. A description of one will do for both, A. fastibilis being a little the more slender of the two. Both have fleshy caps, whitish, moist, and clammy to the touch; instead of a pleasant odor, they have a disagreeable one; the stems are ringless, or nearly so; and the gills, which are palish clay-brown, distinctly touch and grow on to the solid or pithystem. These two fungi usually grow in woods, but sometimes in hedges and in shady places in meadows, or even, as has been said, as invaders on muchroom-beds. The pale clay-colored gills, offensive odor, and clammy or even viscid to pale decisive characters. A reference to the accompanying illustration (fig. 2), which is about one-half natural size will give a good idea of A. fastibilis; the difference in the nature of the attachment of the gills near the stem is seen at R, the absence of a true ring at S, and of a pendent frill at T. The color, with the exception of the gills, is not unlike that of the mushroom. In determining fungi no single character must be relied upon as conclusive, but all the characters must be taken together. Sometimes a beautiful, somewhat slender, fungus peculiar to stumps in woods is mistaken for the mushroom in a cervinus (Sch.); it has a tall, solid, white, ringless stem and somewhat thin brown cap, furnished underneath with beautiful rose-colored gills, which are free from the stem as in the mushroom, and which never turn black. It is probably a poisonous plant, belonging, as it does, to a dangerous cohort. Many other species of Agaricus more or less resemble A. campestris, notably some of the plants found under the sub-genera Lepiota, Volvaria, Pholiota, and Psalliota, but when the characters are noted they may all with a little care be easily distinguished from each other. The better plan is to discard at once all fungi which have not been gathered from open pastures; by this act alone more than nine-tenths of worthless and poisonous species will be excluded.

In cases of poisoning by mushrooms immediate medical advice should be secured. The dangerous principle is a narcotic, and the symptoms are usually great nausea, drowsiness, stupor, and pains in the joints. A good palliative is sweet oil; this will allay any corrosive irritation of the throat and stomach, and at the same time cause vomiting.

The mode of cultivating mushrooms artificially out of doors and in sheds is described under Horticulture, vol. xii. p. 284. Paris mushrooms are cultivated in enormous quantities in dark underground caves at a depth of from 60 to 160 feet from the surface. The stable manure is taken into the tortuous passages of these caves, and the spawn introduced from masses of dry dung where it occurs naturally. In France mushroom-growers do not use the compact blocks or bricks of spawn so familiar in England, but much smaller flakes or "leaves" of dry dung in which the spawn or mycelium can be seen to exist. Less manure is used in these caves than we generally see in the mushroom-houses of England, and the surface of each bed is covered with about an inch of fine white stony soil. The beds are kept artificially moist by the application of water brought from the surface, and the different galleries bear crops in succession. As one is exhausted another is in full bearing, so that by a systematic arrangement a single proprietor will send to the surface from 300 lb to 3000 lb of mushrooms per day. The passages sometimes extend over several miles, the beds sometimes occupying over 20 miles, and, as there are many proprietors of caves, the produce of mushrooms is so large that not only is Paris fully supplied, but vast quantities are forwarded to the different large towns of Europe; the mushrooms are not allowed to reach the fully-expanded condition, but are gathered in a large button state, the whole growth of the mushroom being removed and the hole left in the manure covered with fine earth. The beds remain in bearing for six or eight months, and then the spent manure is taken to the surface again for garden and field purposes. The equable temperature of these caves and their freedom from draught is one cause of their great success; to this must be added the natural virgin spawn, for by continually using spawn taken from mushroom,-producing beds the potency for reproduction is weakened. The beds produce mushrooms in about six weeks after this spawning.

The Fairy-ring Champignon. – This funguys, marasmius Oreades (Fr.), is more universally used in France and Italy than in England although it is well known and frequently used both in a fresh and in a dry state in England. It is totally different in appearance from the Pasture Mushroom, and, like it, its characters are so distinct that there is hardly a possibility of making a mistake when its peculiarities are once comprehended. It has more than one advantage over the Meadow Mushroom in its extreme commonness, its profuse growth, the length of the season in which it may be gathered, the total absence of varietal forms, its adaptability for being dried and preserved for years, and its persistent delicious taste. It is by many esteemed as the best of all the edible fungi found in Great Britain. Like the mushroom, it grows in short open pastures and amongst the short grass of open roadsides; sometimes it appears on lawns, but it never occurs in woods or in damp shady places. Its natural habit is to grow in rings, and the grassy fairy-rings sp frequent amongst the short grass of down and pastures in the spring are generally caused by the nitrogenous manure applied to the soil in the previous autumn by the decay of a circle of these fungi. Many other fungi in addition to the Fairy-ring Champignon grow in circles, so that this habit must merely be taken with its other characters in cases of doubt.

A glance at the illustration (fig. 30 will show entirely the Fairy-ring Champignon differs from the mushroom. In the first place, it is about one-half the size of a mushroom, and whitish-buff in every part, the gills always retaining this color and never becoming salmon- colored, brown, or black. The stem is solid and corky, much more solid than the flesh of the cap, and perfectly smooth, never being furnished with the slighted trace of a ring. The buff-gills are far apart (v), and in this they greatly differ from the somewhat crowded gills of the mushroom; the junction of the gills with the stem (w) also differs in character from the similar junction in the mushroom. The mushroom is a semi-deliquescent fungus which rapidly falls into putridity in decay, whilst the champignon dries up into a leathery substance in the sun, but speedily revives and takes its original form again after the first shower. To this character the fungus owes its generic name (marasmius) as well as one of its most valuable qualities for the table, for examples may be gathered from June to November, and if carefully dried may be hung on strings for culinary purposes and preserved without deterioration for several years; indeed, many persons assert that the rich flavor of these fungi increases with years. Champignons are highly esteemed (and especially is this the case abroad) for adding a most delicious flavor to stews, soups, and gravies.

A fungus which may carelessly be mistaken for the mushroom is M. peronatus (Fr.), but this grows in woods amongst dead leaves, and has a hairy base to the stem and a somewhat acrit taste. Another is M. urens (Fr.); this also generally grows in woods, but the gills are not nearly so deep, they soon become brownish, the stem, is downy, and the taste is acrid. An Agaricus named A. dryophilus (Bull.) has sometimes been gathered in mistake for the champignon, but this too grows in woods where the champignon never grows; it has a hollow instead of a solid stem, gills crowded together instead of far apart, and flesh very tender and brittle instead of tough. A small esculent ally of the champignon, named M. scovodonius (Fr.), is sometimes found in pastures in Great Britain; this is largely consumed on the Continent, where it is esteemed for its powerful flavor of garlic. In England, where garlic is not used to a large extent, this fungus is not sought for. Another small and common species, M. porrcus (Fr.), is pervaded with a garlic flavor to an equal extent with the last. A third species, M alliaceus (Fr.), is also strongly impregnated with the scent and taste of onions or garlic. Two species, M. impudicus (Fr.) and M. foetidus (Fr.), are in all stages of growth highly foetid. The curious little edible Agaricus esculentus (Jacq.), although placed under the sub-genus Collybia, is allied by its structure to Marasmius. It is a small bitter species common in upland pastures and fir plantations early in the season. Although not gathered for the table in England, it is greatly prized in some parts of the continent. Fries, the greatest authority on the higher Fungi, writes: "In Austria in cibariis magni aestumatur." The odor and taste in fungi when raw are often valuable characters in deciding species.

Morel. – This delicious edible fungus, Morchella esculenta (Pers.), is more common in Britain than is generally supposed. It grows after warm rains in the spring or early summer in woody places and in orchards and gardens, often in places where the ground has been burnt. Like the champignon, the morel can be easily dried and kept suspended on strings in necklace fashion for winter use. It is generally 3 or 4 inches high, with a hollow stem and a hollow, irregularly globose, honeycombed head, pale buff in color all over, and furnished with an agreeable odor there is more than one esculent species of morel: M. semilibera (D.C.) is the next best known, but this is rare in Britain. A large species named M. crassipes(pers.). This is a fragrant and delicious species, but only suitable for use in a fresh state; it cannot be readily dried. Another valuable edible species is Gyromitra esculenta (Fr.), recognized by its browning-black globose head; it grows amongst firs and is considered rare.(W. G. SM.)

The above article was written by: Worthington G. Smith; author of Mushrooms and Toadstools: Edible and Poisonous and Diseases of Field and Garden Crops.

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