In those subterranean funguses which mature their seeds below the surface of the ground, the lower portion, so soon as this is accomplished in the upper, suddenly takes to grow upwards, carrying along with it the bag, which, on reaching the surface of the ground, bursts its envelopes and scatters its prolific dust to the winds. All funguses, as has already been observed, have in all probability spores, though in a few instances, of byssoid growths, (Hyphas, Himantias, and Æthelias,) these are not apparent; in most cases too, they are attached to an hymenium, into which, or on the surface of which, they are placed till ripe. One very large tribe, by far the largest, are called Hymenomycetes, from ὑμήν, a membrane, and μύκος, a fungus; i. e. funguses with a seed membrane: to distinguish them from those other kinds, very small numerically in proportion to themselves, Gasteromycetes, in which the seeds, arranged and stored away in particular receptacles, named sporanges or thecæ, are with them included in the belly (γαστήρ) of the fungus, as is the case in truffles and puff-balls. The hymenium, like that curiously doubled-down sheet of paper which conjurors turn into so many shapes, assumes a great variety of forms; running down the gills of the mushrooms and the plaits of the Cantharellus, up into the tubes of the Boletuses; sheathing the vegetable teeth of Hydna, forming an intricate labyrinth of anastomosing plates in Dædalea; now rising into little rough eminences on the surface of the Thelephoræ, and now affording a smooth investment to that of the Clavariæ. It is covered with a veil, which disappears so soon as the spores begin to ripen, and its protection is no longer required; seen under the microscope, it appears to be wholly made up of thecæ.
SUCCESSIVE DEVELOPMENT OF THE SPORES.
When the spore is to cease to be a spore, and to become a mushroom, the first thing it does is to send forth certain cotton-like filaments, whose interfacings entangle it completely while they also serve to attach it to the place of its birth; these threads (like the spongioles attached to the roots of phænogamous plants, whose name sufficiently explains their office) absorb and bring nourishment to the quickened spore, which then maintains itself entirely by intus-susception. All this takes place before the germ has burst, or the embryo fungus begun to develope its organs. In some instances, these elementary threads are, like the ordinary roots of plants, spread out to a considerable distance underground, forming here and there in their course small bulbs or tubercles, each of which, in turn, becomes a new individual; in others, and more commonly, these spores are sprinkled about unconnectedly, as in the Pietra funghaia, affecting certain spots only, which become so many small matrices whereof each furnishes a crop. The union of many germinating granules together with their connecting threads, constitutes mushroom spawn, or, as it is technically called, carcytes.[110] Examined a short time after quickening, the spore is found to have swelled out into a fleshy kernel; which in puff-balls, truffles, and the uterine subterranean families generally, constitutes of itself the whole fungus; this only grows in size afterwards, the substance and original form remaining the same through the entire period of development. In those destined to live under the influence of air and light, this same rudimental nucleus gradually evolves new parts, and assumes, as we have seen, a vast variety of forms, (whereof each particular one is predetermined by the original bias imprinted upon every spore at its creation,) and here there is a manifest analogy with the progressive development of new parts in the higher plants. In such funguses as are wrapped up in a volva or bag, during the earliest period of growth, this furnishes them not only with the means of protection, but of nourishment also. This volva, which is formed by the mere swelling out of the original fleshy bulb, when it has grown to a certain size, exhibits towards its centre the rudiments of the young fungus; of which the receptacle appears first, and all the other parts in succession. The embryo, next taking to grow, in its turn approaches the circumference of the volva, which, having by this time ceased to expand, is burst open, and sometimes with much violence, by the emerging Amanite. As soon as the hymenium has parted with its seed, which falls from it in the form of fine dust, the fungus, collapsing, either withers on its stem, or else dissolves into a black liquid and so escapes to the earth. In such funguses as have not a volva, the basilar or primary nucleus shoots up at once in the form of a cone, and a little later presents at its apex the rudiments of a receptacle or head; by degrees, and frequently by slow degrees,[111] the perfected structures of the plant are elaborated and spread themselves out into some of the forms mentioned above, of which the clavate is the most simple, and that with gills the most complex. The primary nucleus is formed out of simple cellular membrane, the cells of which, at first elongating, and at length uniting into little bundles, assume a fibrous appearance; sometimes these fascicular bodies effuse themselves unchanged into the substance of the receptacle, in which they spread out and are lost; at others, a transverse line makes the demarcation between the pileus and stem.[112] The last part formed in a fungus, generally, is that which bears the seed; and whenever an exception to this occurs, and the seed is formed at an earlier period than usual, nature has in this case provided three membranes, to cover and protect these delicate organs till the plant shall have attained maturity: these are the ring (annulus), the veil (velum), and the wrapper (volva).
OF THE ANNULUS, THE VELUM, AND THE VOLVA.
Of these involucra the first two are partial, the other universal. The Volva is a thick membranaceous covering, originating at the base of the fungus, which it thus connects with the earth, and furnishes, during its fœtal life, with the means of support and nourishment. When this has ceased, and the plant has quitted its wrapper, if this still adhere to the base of the stalk, it is styled manifest (manifesta), but if there be no traces of it left, obliterated (obliterata). It is free when it can be easily detached, and congenital when it cannot without laceration. In funguses with bulbous roots it is congenital, in those without bulbs it is free. All funguses that have a volva are of course volvati, but as this organ exists in many only so long as they are underground, mycologists are agreed to restrict the term to such alone as retain it afterwards.
The Ring.—This, which differs considerably in form, substance, and in its attachments, is composed either of a continuous sheet of membrane or else of a number of delicately-spun threads, resembling a spider’s web,[113] which in either case passing from the margin of the pileus to the corresponding upper portion of the stem, give way as the plant expands, and either festoon for a season the margin of the cap, or encircle the stalk with a ring. The marginal remains of the Annulus are extremely fugacious, but the ring round the stalk, though generally transitory, is sometimes persistent; it is superior or descending when originating from the summit of the stem, it descends outwards and downwards to form connections with the rim of the pileus; inferior or ascending when, coming off from that portion of the stalk which is below the pileus, it ascends to attach itself to this. In a few cases the ring is partly membranaceous and partly composed of radiating arachnoid threads.
The Veil.—Some funguses not only present the ring just mentioned, their hymenium or seed membrane being further protected from harm by a second investment, the veil, Velum, the stalk origin of which, when existing in conjunction with an annulus, is below it, but when the fungus is not annulate, the velum rises higher up on the stalk, stretches across to meet and is afterwards reflected over the whole surface of the pileus; on the expansion of the Agaric this investment is entirely broken up, and exhibits those well-known flocks, which have been called by the learned verrucæ, but which, as they are generally of a dirty leprous hue, and affect more or less of a circular arrangement, have procured for this whole tribe of Amanites in Italy the uncomely epithet of tignosi, or scald-heads. Where there has been both a volva and a velum, as sometimes happens in the same fungus, these verrucæ are of different colours according as they are remnants of the first merely, or of both together.[114] The velum in the subgenus Limacium is a slimy coating adhering to the head of the fungus, which then looks as if it had been dipped in gum mucilage; this generally disappears after a time, leaving the epidermis dry, though sometimes, like the solid membranaceous veil, it is more or less persistent. The waxy covering on the pileus of the Ag. virescens, which after a time cracks and tessellates its surface, is only an exudation limited to the upper portion of the cap, and not a veil.
The Stalk.—This, which is absent in many parasitical funguses of the Order Pileati, when present, either effuses itself uninterruptedly into the substance of the pileus, which it then, in fact, forms, or else supports merely as on a pillar, a distinct line of demarcation showing where the fibres terminate. It assumes a great variety of forms, which serve in many instances to characterize species; besides which peculiarities there are others to be noted, as the mode of its insertion into the pileus, its having or not having a ring, the circumstance of its being scabrous, glossy, or tomentose, reticulated, spotted, or striped, of one colour above and another below, or of its changing colour when bruised, any of which may sometimes assist our diagnosis.