FOOTNOTES:[E]The recipes for Agaricus are intended for the several species of this genus (Psalliota).
[E]The recipes for Agaricus are intended for the several species of this genus (Psalliota).
[E]The recipes for Agaricus are intended for the several species of this genus (Psalliota).
By J. F. CLARK.
Regarding the chemical composition of mushrooms, we have in the past been limited largely to the work of European chemists. Recently, however, some very careful analyses of American mushrooms have been made. The results of these investigations, while in general accord with the work already done in Europe, have emphasized the fact that mushrooms are of very variable composition. That different species should vary greatly was of course to be expected, but we now know that different specimens of the same species grown under different conditions may be markedly different in chemical composition. The chief factors causing this variation are the composition, the moisture content, and the temperature of the soil in which they grow, together with the maturity of the plant. The temperature, humidity, and movement of the atmosphere and other local conditions have a further influence on the amount of water present.
The following table, showing the amounts of the more important constituents in a number of edible American species, has been compiled chiefly from a paper by L. B. Mendel (Amer. Jour. Phy.1: 225–238). This article is one of the most recent and most valuable contributions to this important study, and anyone wishing to look into the methods of research, or desiring more detailed information than is here given, is referred to the original paper.
FRESH MATERIAL.IN WATER-FREE MATERIAL.WATER.DRY MATTER.TOTAL NITROGEN.PROTEID NITROGEN.ETHER EXTRACT.SOLUBLE IN 85 PER CENT ALCOHOL.FIBRE.ASH.%%%%%%%%Coprinus comatus92.197.815.791.923.356.37.312.5Morchella esculenta89.540.464.663.494.829.38.710.4Polyporus sulphureus70.809.203.292.233.227.83.07.3Pleurotus ostreatus73.706.302.401.131.631.57.56.1Clitocybe multiceps89.610.395.361.986.057.29.611.5Hypholoma candolleanum88.971.034.282.492.544.412.113.9Agaricus campestris91.88.24.753.573.72————11.6
Water.—Like all growing plants, the mushroom contains a very large proportion of water. The actual amount present varies greatly in different species. In the above table it will be seen thatPolyporus sulphureus, with over 70 per cent. of water, has the least of any species mentioned, while the species ofCoprinusandAgaricushave usually fully 90 per cent. water. The amount of water present, however, varies greatly in the same species at different seasons and in different localities, and with variations in the moisture content of soil and atmosphere, also with the age and rapidity of development of the individual plant.
Total Nitrogen.—The proportion of nitrogen in the dry matter of different species varies from 2 per cent. to 6 per cent. This comparatively high nitrogen content was formerly taken to indicate an unusual richness in proteid substances, which in turn led to very erroneous ideas regarding the nutritive value of these plants. The nitrogenous substances will be more fully discussed later, when we consider their nutritive value.
Ether Extract.—This consists of a variety of fatty substances soluble in ether. It varies greatly in quality and quantity in different species. The amount is usually from 4 per cent. to 8 per cent. of the total dry matter. It includes, besides various other substances, several free fatty acids and their glycerides, the acids of low melting point being most abundant. These fatty substances occur in the stem, but are much more abundant in the cap, especially in the fruiting portion. Just what nutritive value these fatty matters may have has never been determined.
Carbohydrates.—The largest part of the dry matter of the mushrooms is made up of various carbohydrates, including cellulose or fungocellulose, glycogen, mycoinuline, trehalose, mannite, glucose, and other related substances. The cellulose is present in larger proportion in the stem than in the cap, and in the upper part of the cap than in the fruiting surface. This is doubtless related to the sustaining and protective functions of the stem and the upper part of the cap. Starch, so common as a reserve food in the higher plants, does not occur in the mushrooms. As is the case with the fats, no determination of the nutritive value of these substances has been made, but it may be assumed that the solublecarbohydratesof the mushrooms do not differ greatly from similar compounds in other plants.
Ash.—The ash of mushrooms varies greatly.Polyporus officinalisgives but 1.08 per cent. of ash in dry matter,Pleurotus ulmariusgives 12.6 per cent., andClitopilus prunulusgives 15 per cent. The averageof twelve edible species gave 7 per cent. ash in the stem and 8.96 per cent. in the cap.
In regard to the constituents of the ash, potassium is by far the most abundant—the oxide averaging about 50 per cent. of the total ash. Phosphoric acid stands next to potassium in abundance and importance, constituting, on an average, about one-third of the entire ash. Oxides of manganese and iron are always present; the former averaging about 3 per cent. and the latter 5 per cent. to 2 per cent. of the ash. Sodium, calcium, and chlorine are usually present in small and varying quantities. Sulphuric acid occurs in the ash of all fungi, and is remarkable for the great variation in quantity present in different species; e. g., ash ofHelvella esculentacontains 1.58 per cent. H_2SO_4 while that ofAgaricus campestriscontains the relatively enormous amount of 24.29 per cent.
Any discussion of the bare composition of a food is necessarily incomplete without a consideration of the nutritive value of the various constituents. This is especially desirable in the case of the mushrooms, for while they are frequently overestimated and occasionally ridiculously overpraised by their friends, they are quite generally distrusted and sometimes held in veritable abhorrence by those who are ignorant of their many excellent qualities. On the one hand, we are told that "gastronomically and chemically considered the flesh of the mushroom has been proven to be almost identical with meat, and possesses the same nourishing properties." We frequently hear them referred to as "vegetable beefsteak," "manna of the poor," and other equally extravagant and misleading terms. On the other hand, we see vast quantities of the most delicious food rotting in the fields and woods because they are regarded by the vast majority of the people as "toadstools" and as such particularly repulsive and poisonous.
Foods may be divided into three classes according to the functions they perform:
The formation of the body material and the repair of its wastes is the function of the proteids of foods. It has been found by careful experiment that a man at moderately hard muscular exertion requires .28 lb. of digestible proteids daily. The chief sources of our proteid foods are meats, fish, beans, etc. It has been as a proteid food that mushrooms have been most strongly recommended. Referringto Table I, it will be seen that nitrogen constituted 5.79 per cent. of the total dry substance ofCoprinus comatus. This high nitrogen content, which is common to the mushrooms in general, was formerly taken to indicate a very unusual richness in proteid materials. It is now known, however, that there were several sources of error in this assumption.
Much of the nitrogen is present in the form of non-proteid substances of a very low food value. Another and very considerable portion enters into the composition of a substance closely related to cellulose. A third source of error was the assumption that all the proteid material was digestible. It is now known that a very considerable portion is not digestible and hence not available as food. Thus, notwithstanding the 5.79 per cent. of nitrogen inCoprinus comatus, we find but .82 per cent. in the form of actually available (i. e., digestible) proteids, or approximately one-seventh of what was formerly supposed to be present.
The digestibility of the proteids varies very greatly with the species. Mörner found the common field mushroom,Agaricus campestris, to have a larger amount of proteids available than any other species studied by him. Unfortunately, the digestibility of the American plant has not been tested. There is great need for further work along this line. Enough has been done, however, to demonstrate that mushrooms are no longer to be regarded as a food of the proteid class.
The energy for the muscular exertion and heat is most economically derived from the foods in which the carbohydrates and fats predominate.
The common way of comparing foods of the first two classes scientifically is to compare their heat-giving powers. The unit of measurement is termed acalorie. It represents the amount of heat required to raise a kilogram of water 1° Centigrade. (This is approximately the heat required to raise one pound of water 4° Fahrenheit.) A man at moderately hard muscular labor requires daily enough food to give about 3500caloriesof heat-units. The major part of this food may be most economically derived from the foods of the second class, any deficiency in the .28 lb. of digestible protein being made up by the addition of some food rich in this substance.
In the following table the value of ten pounds of several food substances of the three classes has been worked out. Especial attention is called to the column headed "proteids" and to the last column where the number of heat-units which may be purchased for one cent at current market rates has been worked out.
NUTRITIVE VALUE OF TEN POUNDS OF SEVERAL FOODS.
PROTEIDS.FATS.CARBO-HYDRATES.CALORIES.COST.CALORIESFOR ONECENT.a.Beef (round)1.87.88——7200$1.5048.Beans (dried)2.23.185.9115900.30530.b.Cabbage.18.03.491400.1593.Potatoes.18.011.533250.10325.Flour (roller process)1.13.117.4616450.25658.c.Coprinus comatus.04.025.4349872.503.9Pleurotus ostreatus.051.042.82818112.507.2Morchella esculenta.094.05.3069552.503.8Agaricus campestris.18.03.4613162.505.3Oysters.61.14.3323502.0011.7
The mushrooms have been valued at 25 cents per pound, which is probably considerably below the average market price for a good article. It should also be remarked that the amounts given in this table are the digestible and hence available constituents of the foods. The only exception to this is in the case of the fats and carbohydrates of the mushrooms, no digestion experiments having been reported on these constituents. In the absence of data we have assumed that they were entirely digested.
The beef and beans are typical animal and vegetable foods of the proteid class. A glance at the table will show how markedly they differ from the mushrooms. The latter are nearest the cabbage in composition and nutritive value. The similarity between the cabbage and theAgaricus campestrishere analyzed is very striking. The potato is somewhat poorer in fat, but very much richer than the mushroom in carbohydrates.
The figures in the last column will vary of course with fluctuations in the market price, but such variation will not interfere at any time with the demonstration thatpurchasedmushrooms are not a poor man's food. Here we find that one cent invested in cabbage at 1-1/2 cents per pound, gives 93caloriesof nutrition, while the same amount invested inAgaricus campestris—the common mushroom of our markets—would give but 5.3calories, although they are almost identical so far as nutritive value is concerned.
The same sum invested in wheat flour, with its high carbohydrate and good proteid content, would yield 658caloriesor one-sixth the amount necessary to sustain a man at work for one day. The amount of mushrooms necessary for the same result is a matter of simple computation.
Mushrooms, however, have a distinct and very great value as a food of the third class, that is, as condiments or food accessories, and their value as such is beyond the computation of the chemist or the physiologist, and doubtless varies with different individuals. They are among the most appetizing of table delicacies and add greatly to the palatability of many foods when cooked with them. It is surely as unfair to decry the mushroom on account of its low nutritive value, as it is wrong to attribute to it qualities which are nothing short of absurd in view of its composition. In some respects its place as a food is not unlike that of the oyster, celery, berries, and other delicacies. Worked out on the basis of nutritive value alone they would all be condemned; the oyster for instance presents a showing but little better than the mushroom, and vastly inferior, so far as economy is concerned, to the common potato. This, too, for oysterspurchased by the quart. The nutritive value of one cent's worth of oysters "on the half shell" would be interesting!
The question of the toxicology of the higher fungi is one of very great theoretical and practical interest. But on account of the great difficulties in the way of such investigations comparatively little has yet been accomplished. A few toxic compounds belonging chiefly to the class termed alkaloids have, however, been definitely isolated.
Choline.—This alkaloid is of wide occurrence in the animal and vegetable kingdoms. It has been isolated fromAmanita muscaria,A. pantherina,Boletus luridus, andHelvella esculenta. It is not very toxic, but on uniting with oxygen it passes over to muscarine. According to Kobert the substance formed from choline on the decay of the mushrooms containing it is not muscarine, but a very closely related alkaloid,neurin. This transformation of a comparatively harmless alkaloid to an extremely deadly one simply by the partial decay of the plant in which the former is normally found, emphasizes very much the wisdom of rejecting for table use all specimens which are not entirely fresh. This advice applies to all kinds of mushrooms, and to worm-eaten and otherwise injured, as well as decayed ones. Neurin is almost identical in its physiological effects with muscarine, which is described below.
Muscarine.—This is the most important because the most dangerous alkaloid found in the mushrooms. It is most abundant inAmanita muscaria, it is also found in considerable quantity inAmanita pantherina, and to a lesser, but still very dangerous extent inBoletus luridusandRussula emetica. It is quite probably identical with bulbosine, isolated fromAmanita phalloidesby Boudier.Muscarineis an extremely violent poison, .003 to .005 of a gram (.06 grain) being a very dangerous dose for a man. Like other constituents of mushrooms, the amount of muscarine present varies very greatly with varying conditions of soil and climate. This, indeed, may account for the fact thatBoletus luridusis regarded as an edible mushroom in certain parts of Europe, the environment being such that little or no muscarine is developed.
According to Kobert,Amanita muscariacontains, besides choline and muscarine, a third alkaloid,pilz-atropin. This alkaloid, like ordinary atropin, neutralizes to a greater or less extent the muscarine. The amount of pilz-atropin present varies, as other constituents of mushrooms vary, with varying conditions of soil, climate, etc., and it may be that in those localities where theAmanita muscariais used for food the conditions are favorable for a large production of pilz-atropin which neutralizes the muscarine, thus makingthe plant harmless. Be this as it may,Amanita muscaria, so deadly as ordinarily found, is undoubtedly used quite largely as food in parts of France and Russia, and it has been eaten repeatedly in certain localities in this country without harm.
Fortunately muscarine has a very unpleasant taste. It is interesting in this connection to note that theAmanita muscariais said to be used by the inhabitants of Northern Russia—particularly the Koraks—as a means of inducing intoxication. To overcome the extremely unpleasant taste of the plant they swallow pieces of the dried cap without chewing them, or boil them in water and drink the decoction with other substances which disguise the taste.
The symptoms of poisoning with muscarine are not at once evident, as is the case with several of the less virulent poisons. They usually appear in from one-half to two hours. For the symptoms in detail we shall quote from Mr. V. K. Chestnut, Dept. of Agr., Washington (Circular No. 13, Div. of Bot.): "Vomiting and diarrhœa almost always occur, with a pronounced flow of saliva, suppression of the urine, and various cerebral phenomena beginning with giddiness, loss of confidence in one's ability to make ordinary movements, and derangements of vision. This is succeeded by stupor, cold sweats, and a very marked weakening of the heart's action. In case of rapid recovery the stupor is short and usually marked with mild delirium. In fatal cases the stupor continues from one to two or three days, and death at last ensues from the gradual weakening and final stoppage of the heart's action."
The treatment for poisoning by muscarine consists primarily in removing the unabsorbed portion of the mushroom from the alimentary canal and in counteracting the effect of muscarine on the heart. The action of this organ should be fortified at once by the subcutaneous injection, by a physician, of atropine in doses of from one one-hundredth to one-fiftieth of a grain. The strongest emetics, such as sulphate of zinc or apomorphine, should be used, though in case of profound stupor even these may not produce the desired action. Freshly ignited charcoal or two grains of a one per cent. alkaline solution of permanganate of potash may then be administered, in order, in the case of the former substance, to absorb the poison, or, in the case of the latter, to decompose it. This should be followed by oils or oleaginous purgatives, and the intestines should be cleaned and washed out with an enema of warm water and turpentine.
Experiments on animals poisoned byAmanita muscariaand with pure muscarine show very clearly that when the heart has nearly ceased to beat it may be stimulated to strong action almost instantlyby the use of atropine. Its use as thus demonstrated has been the means of saving numerous lives. We have in this alkaloid an almost perfect physiological antidote for muscarine, and therefore in such cases of poisoning its use should be pushed as heroically as the symptoms of the case will warrant. The presence of phallin inAmanita muscariais possible, and its symptoms should be looked for in the red color of the blood serum discharged from the intestines.
Phallin.—The exact chemical nature of this extremely toxic substance is not certainly known, but it is generally conceded to be of an albuminous nature. That it is an extremely deadly poison is shown by the fact that .0015 grain per 2 lbs. weight of the animal is a fatal dose for cats and dogs. It is the active principle of the most deadly of all mushrooms, theAmanita phalloides, or death-cup fungus. We quote again from Mr. Chestnut's account of phallin and its treatment: "The fundamental injury is not due, as in the case of muscarine, to a paralysis of the nerves controlling the action of the heart, but to a direct effect on the blood corpuscles. These are quickly dissolved by phallin, the blood serum escaping from the blood vessels into the alimentary canal, and the whole system being rapidly drained of its vitality. No bad taste warns the victim, nor do the preliminary symptoms begin until nine to fourteen hours after the poisonous mushrooms are eaten. There is then considerable abdominal pain and there may be cramps in the legs and other nervous phenomena, such as convulsions, and even lockjaw or other kinds of tetanic spasms. The pulse is weak, the abdominal pain is rapidly followed by nausea, vomiting, and extreme diarrhœa, the intestinal discharges assuming the 'rice-water' condition characteristic of cholera. The latter symptoms are persistently maintained, generally without loss of consciousness, until death ensues, which happens in from two to four days. There is no known antidote by which the effects of phallin can be counteracted. The undigested material, if not already vomited, should, however, be removed from the stomach and intestines by methods similar to those given for cases of poisoning byAmanita muscaria.
"After that the remainder of the poison, if the amount of phallin already taken up by the system is not too large, may wear itself out on the blood and the patient may recover. It is suggested that this wearing-out process may be assisted by transfusing into the veins blood freshly taken from some warm-blooded animal. The depletion of the blood serum might be remedied by similar transfusions of salt and warm water."
Helvellic Acid.—This very deadly poison is sometimes found inHelvella esculentaPersoon (Gyromitra esculenta), particularly in old or decaying specimens. It has been studied and named by Boehm. It is quite soluble in hot water, and in some localities this species ofHelvellais always parboiled—the water being thrown away—before it is prepared for the table. It seems to be quite generally agreed that young and perfectly fresh specimens are free from the poison. As the poison is very violent, however, this plant should be carefully avoided.
The symptoms resemble in a very marked degree those of the deadly phallin, the dissolution of the red corpuscles of the blood being one of the most marked and most dangerous; this is accompanied by nausea, vomiting, jaundice, and stoppage of the kidneys. There is no known antidote for this poison, hence the little that can be done would be similar to that mentioned under phallin.
When poisoning by mushrooms is suspected, one cannot too strongly urge that the services of a competent physician should be secured with the least possible delay.
By H. HASSELBRING.
In fungi, as in higher plants, each organ or part of the plant is subject to a great number of variations which appeal to the eye of the student, and by which he recognizes relationship among the various individuals, species, and genera of this group. For the purpose of systematic studies of mushrooms or even for the recognition of a few species, it is of primary importance to be acquainted with terms used in describing different types of variation. Only a few of the more important terms, such as are employed in this book, together with diagrams illustrating typical cases to which they are applied, will be given here.
The pileus.—Thepileusorcapis the first part of a mushroom which attracts the attention of the collector. It is the fleshy fruit body of the plant. This, like all other parts of the mushroom, is made up, not of cellular tissue as we find it in flowering plants, but of numerous interwoven threads, calledhyphæ, which constitute the flesh ortramaof the pileus. Ordinarily, the filamentous structure of theflesh is very obvious when a thin section of the cap is examined under the microscope, but in certain genera, asRussulaandLactarius, many branches of thehyphæbecome greatly enlarged, forming little vesicles or bladders. These vesicles lie in groups all through the flesh of the pileus, sometimes forming the greater part of its substance. The filamentoushyphæpass around and through these groups, filling up the interstices. In cross section this tissue resembles parenchyma, and appears as if it were made up of rounded cells. Such a trama is said to bevesiculoseto distinguish it from the ordinary orfloccosetrama. The threads on the outer surface of the pileus constitute the cortex or cuticle. They are thick walled and often contain coloring matter which gives the plants their characteristic color. In many species their walls become gelatinized, covering the outside of the pileus with a viscid, slimy, or glutinous layer, often calledpellicle. In other instances the corticle layer ceases to grow with the pileus. It is then torn and split by the continued expanding of the rest of the plant, and remains on the surface in the form of hairs, fibers, scales, etc.
Figure 239.Figure 240.Portion of vesiculose tramain the pileus of a Russula.Portion of a floccose trama.
As an example of the most usual form of the pileus, we may take that of the common mushroom (Agaricus campestris) when it is nearly expanded. The pileus is then quite regular in outline and evenlyconvex(Fig. 243). Many mushrooms during the early stages of their development have this form, which is variously changed by latergrowth. The convex pileus usually becomesplaneorexpandedas it grows. If the convexity is greater it is said to becampanulate(Fig.245),conical hemispherical, etc., terms which need no explanation. The pileus isumbilicatewhen it has an abrupt, sharp depression at the center (Fig. 241),infundibuliformwhen the margin is much higher than the center, so that the cap resembles a funnel (Fig.244), anddepressedwhen the center is less, or irregularly, sunken. When the center of the pileus is raised in the form of a boss or knob it isumbonate(Fig.242). The umbo may have the form of a sharp elevation at the center, or it may be rounded or obtuse, occupying a larger part of the disc. When it is irregular or indistinct the pileus is said to begibbous(Fig.246).
Figure 241.—Omphalia campanella, pileus umbilicate, gills decurrent.Figure 242.—Lepiota procera, pileus convex, umbonate; annulus free, movable; gills free.Figure 243.—Agaricus campestris, pileus convex, gills free.
The gills.—Thegillsorlamellæare thin blades on the under sideof the pileus, radiating from the stem to the margin. When the pileus is cut in halves the general outline of the gills may be observed. In outline they may be broad, narrow, lanceolate, triangular, etc. In respect to their ends they areattenuatewhen gradually narrowed to a sharp point,acutewhen they end in a sharp angle, andobtusewhen the ends are rounded. Again, the gills arearcuatewhen they arch from the stem to the edge of the pileus, andventricosewhen they are bellied out vertically toward the earth.
Figure 244.Figure 245.Clitocybe infundibuliformis, pileusinfundibuliform, gills decurrent.Mycena galericulata, pileusconic to campanulate, gillsdecurrent by a tooth, stem fistulose.
The terms given above are often used in descriptive works, but the most important feature to be noted in the section of the plant is the relation of the gills to the stem. This relation is represented by several distinct types which are sometimes used to limit genera or sub-genera, since the mode of attachment is usually constant in all species of a group. The principal relations of the gills to the stem are described as follows:Adnatewhen they reach the stem and are set squarely against it (Fig.247);decurrentwhen they run down the stem (Fig.244);sinuateoremarginatewhen they have a notch or vertical curve at the posterior end (Fig.246); andfreewhen theyare rounded off without reaching the stem (Fig.243). In all cases when the lamellæ reach the stem and are only attached by the upper angle they are said to beadnexed. This term is often used in combination with others, assinuate-adnexed(Fig.248, small figure), orascending adnexed(Fig. 248, larger plant). Sometimes the lamellæ are adnate, adnexed, etc., and have a slight decurrent process or tooth as inMycena galericulata(Fig.245). In many plants the gills separate very readily from the stem when the plants are handled. Sometimes merely the expansion of the pileus tears them away, so that it is necessary to use great caution, and often to examine plants in different stages of development to determine the real condition of the lamellæ.
Figure 246.—Tricholoma, gills sinuate, stipe solid.Figure 247.—Panæolus papilionaceus, gills adnate.Figure 248.—Left-hand small plant, Hygrophorus, gills sinuate, adnexed. Right-hand plant Panæolus retirugis, gills ascending adnexed, veil appendiculate.
In certain genera the gills have special characteristics which may be noted here. Usually the edge of the lamellæ isacuteor sharp like the blade of a knife, but inCantharellusandTrogiathe edges are very blunt or obtuse. In extreme forms the lamellæ are reduced tomere veins or ridges. Again, the edge is generallyentire, i. e., not noticeably toothed, but inLentinusit is often toothed or cut in various ways. In some other plants the edges areserrulate,crenulate, etc. InSchizophyllum alneum, a small whitish plant very common on dead sticks, the gills are split lengthwise along the edge with the halves revolute, i. e., rolled back. InCoprinusthe gills and often a large part of the pileus melt at maturity into a dark, inky fluid.
Figure 249.—Section of portion of gill of Marasmius cohærens.t, trama of gill;sh, sub-hymenium;h, hymenium layer. The long, dark cells are brown cystidia, termed spicules by some to distinguish them from the colorless cystidia. The long cells bearing the oval spores are the basidia.
Figure 249.—Section of portion of gill of Marasmius cohærens.t, trama of gill;sh, sub-hymenium;h, hymenium layer. The long, dark cells are brown cystidia, termed spicules by some to distinguish them from the colorless cystidia. The long cells bearing the oval spores are the basidia.
Figure 250.—Inocybe repanda (Bull.) Bres. (= Entoloma repandum Bull.).t, trama of pileus;sh, sub-hymenium;h, the hymenial layer; the long cells with a drop of moisture at the ends are cystidia (sing. cystidium).
Figure 250.—Inocybe repanda (Bull.) Bres. (= Entoloma repandum Bull.).t, trama of pileus;sh, sub-hymenium;h, the hymenial layer; the long cells with a drop of moisture at the ends are cystidia (sing. cystidium).
The hymenium.—The termhymeniumis applied to the spore-bearing tissue of many fungi. In theAgaricaceæthe hymenium covers the entire surface of the gills and usually the portion of the pileus between the gills. It originates in the following manner: the threads forming the trama of the gills grow out from the lower side of the pileus and perpendicular to its under surface. As growth advances many branches of the threads turn outward toward either surface of the gill and finally terminate in club-shaped cells. These cells, therefore, lie side by side, perpendicular to the surface,forming a pavement, as it were, over the entire surface of the gills. Some of them put out four little prongs, on each of which a spore is borne, while others simply remain as sterile cells (Figs.249,250). The spore-bearing cells arebasidia; the others are calledparaphyses. They resemble each other very much, except that the basidia bear foursterigmataand a spore on each. In a few species the number of sterigmata is reduced to two and in some low forms the number is variable. The layer just beneath the basidia is usually more or less modified, being often composed of small cells different from the rest of the trama. This is called thesub-hymeniallayer orsub-hymenium(Fig.250).
Other cells calledcystidiaoccur in the hymenia of various species distributed through nearly all the genera of the agarics. Cystidia are large, usually inflated, cells which project above the rest of the hymenium (Fig.250). They originate either like the basidia, from the sub-hymenial cells (Fig.250), or from special hyphæ deeper down in the trama of the gill (Fig.249). They are scattered over the entire surface of the hymenium, but become more numerous on the edge of the lamellæ. Their number is much smaller than that of the basidia, but in some species where they are colored they may greatly change the appearance of the gills. Cystidia often secrete moisture which collects in drops at their tips, a phenomenon common to all free fungous cells.
The stem.—The stem is usually fixed to the center of the pileus, but it may beeccentric, i. e., fixed to one side of the center, or entirely lateral. When the stem is wanting the pileus issessile. With regard to its interior the stem issolid, when it is evenly fleshy throughout (Fig.246), orhollowwhen the interior is occupied by a cavity (Fig. 248). If the cavity is narrow and tubular the stem isfistulose(Fig. 245); and if the center is filled with a pithy substance it isstuffed(Fig.243). These terms apply only to the natural condition of the stem, and not the condition brought about by larvæ, which eat out the interior of the stem, causing it to be hollow or fistulose.
The terms applicable to the consistency of the stem are difficult to define. In general, stems may be eitherfleshyorcartilaginous. The meaning of these terms can best be learned by careful study of specimens of each, but a few general characters can be given here. Fleshy, fibrous stems occur in the generaClitocybeandTricholoma, among the white-spored forms. Their consistency is like that of the pileus, namely, made up of fleshy, fibrous tissue. They are usually stout, compared with the size of the plant, and when bent or brokenthey seem to be more or less spongy or tough, fibrous, so that they do not snap readily. Cartilaginous stems have a consistency resembling that of cartilage. Their texture is always different from that of the pileus, which is fleshy or membranous. In general such stems are rather slender, in many genera rather thin, but firm. When bent sufficiently they either snap suddenly, or break like a green straw, without separating. In regard to their external appearance some resemble fibrous stems, while others are smooth and polished as inMycenaandOmphalia.
The veil.—In the young stages of development the margin of the pileus lies in close contact with the stipe, the line of separation being indicated by a kind of furrow which runs around the young button mushroom. In many genera, asCollybia,Mycena,Omphalia, etc., the pileus simply expands without having its margin ever united to the stipe by any special structure, but in other forms, which include by far the greater number of genera of theAgaricaceæand someBoleti, the interval between the stem and pileus is bridged over by threads growing from the margin of the pileus and from the outer layers of the stem. These threads interlace to form a delicate membrane, known as theveil, which closes the gap between the stem and pileus and covers over the young hymenium.
The veil remains firm for a time, but it is finally torn by the expanding pileus, and its remnants persist on the cap and stem in the form of various appendages, whose character depends on the character of the veil. InCortinariusthe veil is made up of delicate threads extending radially from the stem to the margin of the cap without forming a true membrane. From its resemblance to a spider's web such a veil is said to bearachnoid. At maturity mere traces of it can be found on the stem. In many genera the veil consists of a delicate membrane which tears away from the stem and hangs in flakes to the margin of the pileus. In these cases the veil isappendiculate(Fig. 248). Frequently it is so delicate that no trace of it remains on the mature plant. Where the veil is well developed it usually remains on the stem as aringorannuluswhich becomes free and movable in species ofLepiota(Fig.242) andCoprinus, or forms a hanging annular curtain inAmanita, or a thick, felty ring inAgaricus, etc. In some plants (species ofLepiota) the annulus is continuous with the outer cortex of the stem, which then appears as if it were partially enclosed in a sheath, with the annulus forming a fringe on the upper end of the sheath, from which the apex of the stem projects.
No reference is here made to thevolva, which encloses the entireplant, and which is described in connection with the genera in which it occurs.
The few typical characters described here will help the student to become familiar with terms applied to them. In nature, however, typical cases rarely exist, and it is often necessary to draw distinction between differences so slight that it is almost impossible to describe them. Only by patient study and a thorough acquaintance with the characters of each genus can one hope to become familiar with the many mushrooms growing in our woods and fields.
By the Author.
Plants of large or medium size; fleshy, membranaceous, leathery, woody or gelatinous; growing on the ground, on wood or decaying organic matter; usually saprophytic, more rarely parasitic. Fruiting surface, or hymenium, formed of numerous crowded perpendicular basidia, the apex of the latter bearing two to six (usually four) basidiospores, or the basidiospores borne laterally; in many cases cystidia intermingled with the basidia. Hymenium either free at the beginning, or enclosed either permanently or temporarily in a more or less perfect peridium or veil. Basidiospores continuous or rarely septate, globose, obovoid, ellipsoidal to oblong, smooth or roughened, hyaline or colored, borne singly at the apex of sterigmata.
OrderGasteromycetes. Plants membranaceous, leathery or fleshy, furnished with a peridium and gleba, the latter being sometimes supported on a receptacle. Hymenium on the surface of the gleba which is enclosed within the peridium up to the maturity of the spores or longer; spores continuous, sphæroid or ellipsoid, hyaline or colored. Puff-balls, etc.
OrderHymenomycetes. Hymenium, at the beginning, borne on the free outer surface of the compound sporophore, or if at first enclosed by a pseudo-peridium or veil it soon becomes exposed before the maturity of the spores; mushrooms, etc.
Analytical Key of the Families.