Part 3

In the Hydnei, spine-bearing mushrooms, the hymenium is seen covering the spines or needle-like processes which take the place of gills in this order, and which project from the under surface of the cap. These spines may be divided or entire, simple or ramified, and are formed of the substance of the cap. In the early stages of development they appear like small projecting points or papillae, those on the margin of the cap and at the apex of the stem being always less developed, frequently remaining in this rudimentary state. They are rounded in the species Hydnum imbricatum, sometimes compressed in Hydnum repandum, sometimes terminating in hairs or filaments, as in Hydnum barba Jovis, or very much divided, as in Hydnum fimbriatum.

In the Clavarei, the whole plant consists of solid fleshy masses without any stem of a distinct substance, sometimes club-shaped, sometimes branched with the hymenium smoothly covering the entire surface, never incrusting or coriaceous.

In the Thelephorei, the lower surface of the cap presents neither gills, pores, nor spines, but instead the hymenium covers an uneven or slightly wrinkled surface, partially striate, sometimes obscurely papillose. The plants of this order assume a great variety of shape, from that of a perfect cup with a central stem to an irregularly and much branched frond. They are generally dry and tough. Very few are recommended as edible. Prof. Peck says of this order that probably no edible species will be found in any of its genera outside of the genus Craterellus.

In the order Tremellini we have a great departure from the character of the substance, external appearance, and internal structure of the other orders of the Hymenomycetes. The substance is gelatinous; the form is lobed, folded, or convolute, often resembling the brain of some animal. It is uniformly composed throughout of a colorless mucilage, with no appreciable texture, in which are distributed very fine, diversely branched, and anastomosing filaments. Towards the surface the ultimate branches of this filamentous network give birth to globular cells, both at their summits and laterally, which attain a comparatively large size. These cells are filled with a protoplasm, to which the plant owes its color. The fertile threads are not compacted into a true hymenium.

Representative types of the above-described orders of the Hymenomycetes are shown in Plate B. The various genera, and species of these orders, will be described more in detail in connection with the species illustrated.

CLASSIFICATION.

Owing to the fact that botanists of various countries, writing in diverse languages, have for more than a century been engaged in describing the fungi of their respective countries, with their work frequently unknown to one another, it is not surprising that there has been constant revision, or that many changes have been made in the way of classification and nomenclature which to the amateur student are often confusing.

The classification by the pioneer mycologist, Elias Fries, as presented in his several works on fungi, ignored all microscopical characters, and Saccardo's classification, as presented in his Sylloge Fungorum, was the first complete system offered in its place.

Saccardo, in 1882, commenced his Sylloge, of which not less than twelve volumes have been published. In Saccardo's system of classification the six orders of the Hymenomycetes are not essentially different in their arrangement from that of Fries, although Saccardo has raised all the subgenera of Agaricus to the rank of genera, and then altered their sequence so as to bring them into four sections, distinguished by the color of their spores. Having raised the old subgenera of Fries to generic rank, Saccardo found it necessary to limit the application of the term Agaricus to the group of fungi to which it was originally applied by Linnaeus, viz., the common field mushroom Agaricus campester, and its allies, represented by Agaricus arvensis, Agaricus Rodmani, etc., or, as Prof. Peck more definitely states it, "to those of the gilled mushrooms which have brown spores, free gills, a stem bearing a ring, gills generally pink-colored in the early stage, and brownish black when fully matured." M. C. Cooke, the distinguished English mycologist, prefers to retain the genus Agaricus with its original subgenera intact, succeeded by the other genera of Agaricini, as in the Hymenomycetes Europei of Fries, giving as his reason the belief "that for purposes of classification features should be taken which are present and evident in the specimens themselves, and are not dependent on any of their life-history which cannot be presented in the herbarium."

In a work such as the present, which is designed to be popular in character rather than purely technical, it is deemed advisable to select as a basis for classification that system which is most accessible to reference by the general reading public. Saccardo's Sylloge, while exhaustive in character and of inestimable value to the mycologist, is written in Latin, and is, moreover, a very expensive work--facts which render it practically unavailable to the general public.

In the compilation of this series of pamphlets I have adopted the classification of M. C. Cooke, which, as regards the Hymenomycetes, the family containing most of the fleshy fungi, is, with exceptions noted, in accord with that of Saccardo. M. C. Cooke's hand-book of fungi is of convenient size and form for ready reference.

For the convenience, however, of those who may wish to familiarize themselves with both systems, a synopsis of Saccardo's Genera of Hymenomycetes will be given later.

STRUCTURAL CHARACTERISTICS OF THE AGARICINI.

By far the greater number of the Agaricini have both cap and stem. The form of the cap, as well as that of the stem, varies somewhat in the different genera and species. Those which are terrestrial in habit are generally of an umbrella-like shape, while those which grow upon trees and decayed tree-stumps are apt to be one-sided or semi-spherical.

In many of the parasitical mushrooms the stem is absent. Where the stem is present it is either an interrupted continuation of the hymenophore or fleshy substance of the cap, or else is supported separately as a pillar on which the cap rests, a more or less distinct line of demarcation showing where the fibers terminate. Sometimes it is quite easily detached from the cap socket, as in the Lepiota procerus. It may be hollow or stuffed, solid or fibrillose. It varies in length and thickness. In some species it is smooth and polished, in others rough and hairy, reticulated, etc., sometimes tapering, sometimes distinctly bulbous at the base.

The spores of the species differ in color and are usually globular or oblong in shape. All of these characteristics assist in determining the species.

MUSHROOM GILLS.

Mushroom gills, or lamellae, anatomically considered, are composed, first, of a central portion, a prolongation of the hymenophore or flesh of the cap, more or less dense, sometimes so thin as to be scarcely perceptible; second, the hymenium or spore-bearing membrane covering the surfaces of this prolonged hymenophore. They are vertical, simple, equal, respectively, or more frequently alternating with shorter gills. They are often evanescent and putrescent, sometimes liquefying altogether. Their color is usually different from the upper surface of the cap, not always similar to that of the spores borne upon them, at least in youth; with age, however, they usually assume the color of the mature spore. The change of color of the gills according to the age of the plant is very important in the study of the Agaricini; it accounts for the white gills of certain species in youth, the pink in maturity, and the brown when aged.

The end of the gill nearest the stalk of the plant is termed the posterior extremity; the opposite end, the anterior extremity. In most of the Agaricini the gills are unequal. Some extend from the margin to about half the space between it and the stem; others are still shorter.

THE VOLVA.

The volva is a membrane which envelops the entire plant in embryo, giving it the appearance of an egg. It originates at the base of the mushroom and furnishes it, during its foetal life, with the means of support and nourishment. Its texture is so delicate that it generally disappears, leaving very little trace of its existence on the adult plant. In many of the volvate species this organ exists only so long as they are under ground, and some mycologists restrict the term "volvati" to such only as retain it afterwards. As the young plant expands it breaks through the top of this volva or wrapper, and, emerging, carries with it patches of the membrane on the upper surface of the cap. These are more or less prominent, numerous, and thick, sometimes irregularly disposed, sometimes regularly in the form of plates, warts, etc. At the base of the stem of the mushroom the remains of the volva are seen in the form of a sort of wrapper. This is more or less ample, thick, and ascending. It is called free when it is loose or easily detached from the stem, and congenital when it cannot be separated from it without laceration. In some species it is distinctly membranous, and in others floccose, and friable in character, sometimes appearing in ridges as a mere border, at others broken up into scales, and, as the plant matures, wholly disappearing. The volva is a feature of great importance in the study of the Agaricini, of the subgenera Amanita, Volvaria, etc.

THE MUSHROOM VEIL.

The veil is not a constant feature in the Agaricini, at least it is not always visible. When present it consists of a membrane which extends from the margin of the cap to the stem, veiling or protecting the gills. This membrane, called the cortina, has given its name to a numerous and important class of mushrooms (the Cortinarias). It is generally white, soft, slightly spongy, cottony, at times fibrillose or even slightly fibrous, again in texture comparable to the spider's web, and may be even powdery or glutinous. It exists intact only in the youth of the plant. It is not visible in the developing mushroom, at least while the cap is closely pressed against the stem, but as the cap expands the membrane extends and finally breaks, leaving in some species its remnants upon the margin of the cap and upon the stem in the usual form of a ring or a mere zone. When the stem is not ringed the veil rises high upon the stalk, stretches across to meet the edges of the cap, and is afterwards reflected back over its whole surface.

MUSHROOM SPORES AND MYCELIUM.

The spore is the reproductive organ of the mushroom. It differs from the seed of the flowering plant in being destitute of an apparent embryo. A seed contains a plantlet which develops as such. A spore is a minute cell containing a nucleus or living germ, the reproductive cell germ called by some authors the germinating granule. This in turn throws out a highly elongated process consisting of a series of thread-like cells branching longitudinally and laterally, at length bifurcating and anastomosing the mass, forming the vegetative process known as mycelium or mushroom spawn.

On this mycelium, at intervals, appear knob-like bodies, called tubercles, from which the mushrooms spring and from which they derive their nourishment. See Fig. 5, Plate A.

Where the conditions have been unfavorable this mycelium has been known to grow for years without bearing fruit.

Mushroom spores are very variable in size, shape, and color, but are generally constant at maturity in the same genus. Their shape, almost always spherical in the young plant, becomes ovate, ellipsoidal, fusiform, reniform, smooth, stellate, sometimes tuberculate, or remains globose. This feature, varying thus with the age of the plant, should be studied in the mature plant.