Spores or Seeds
All funguses have not seeds,—at least, seeds apparent to us;106 but if we reflect that these, even where visible, can do no more than present to our senses the visible tabernacle of that life which is still invisible, and which, not being material, must ever elude our search,107 then it will not appear so difficult to conceive that the apparently seedless threads of some particular moulds should include, in their interior, vital germs of some sort, which, being homogeneous with, or of the same colour as, the parenchyma of the mould itself, are invisible—just as we know them to be for a season in puff-balls, in the veins of truffles, or in the Agyrium, the receptacle of which last breaks up, when ripe, into sporidia, which then and not till then become manifest. The seeds of funguses are called spores: in the great majority of cases, the microscope, which brings their shapes under observation (for to the naked eye they appear as dust), presents them to us as round, oval, oblong, or even angular corpuscules, and, more rarely still, echinulate or with a tail. They are as various in size as in shape, the first bearing no proportion whatever to the dimensions of the future plant. They vary, too, greatly in colour, being sometimes of a pure white, and continuing so throughout the whole of their seminal existence; at other times, the white acquires a yellow tinge on drying. Some are brown, some yellow, some pink, some purple, some purple-black, and some pass successively from pink to purple, and from purple to purple-black.108 These seeds or spores are sometimes naked, but are much more commonly shut up in little pouches or receptacles, either of a regular or of an irregular shape; the first are called thecæ, the latter sporanges; thecæ (which are in shape similar to the cases of the same name that used to receive the ancient εἱλίγματα, or scrolls) are small, cylindrical bodies, in which the seeds lie one over the other, as in a rouleau; they are themselves let into a receptacle (or that part of the fungus the office of which is to receive and support the reproductive organs) in a regular and symmetrical manner, and at length occupy it completely. Not all are prolific; for some, pressing upon others, cause them to abort, leaving wherever this happens, sterile thecæ, or paraphyses, between those that are fertile. Sporanges are little globose or turbinated receptacles, frequently furnished with a pedicle, in which the seeds lie without order, as they are themselves inserted symmetrically, or without order, into the receptacle. Sometimes these seeds are packed in series of fours, as in the fimetary Agarics; in other genera, as in the Helvellæ and Morels, they are stored away in series of eights. The spores, so soon as they are ripe, either drop out of the sporiferous membrane (hymenium), or, as more frequently happens, are projected from it with an elastic jerk, or else, as is the case of Agarics of a deliquescent kind, return to the earth mixed up with the black liquid into which these ultimately resolve themselves. Sometimes the whole external surface of the fungus is dusted with seed; but much more frequently they are restricted to some particular part, and either lie on the upper side, as in the Pezizæ, or on that which is beneath, as in the mushroom. The spores generally lie on the outside of the fungus, but in the puff-ball, as every one knows, they are internal, and in such prodigious quantity as sometimes entirely to fill its cavity. It is a speculation from Germany, that spores are capable of altering their forms, and that according to the accidents of climate or soil, they assume this or that type, and give rise at different times to different kinds of funguses; on which it is sufficient to remark, that while there is not the least foundation for such an hypothesis, there is in fact much evidence against it; nature acts by immutable laws and has no changelings. To appeal to experience, when did mushrooms ever spawn toadstools? When was the Pietra funghaia ever seen to bring forth anything but its own Polyporus? or the fig, the poplar, or the hazel (when singed and watered to render them prolific) exhibit any but their own particular mushroom? Spores are endowed, like other seeds, with an extraordinary vitality, which may lie dormant in them for an indefinite period; but unlike most other seeds, they seem capable of resisting the prolonged heat of boiling water, infused in which, and poured upon the ground, they are still capable of producing each after its kind. The specific gravity of spores is greater than that of water, as may be seen by placing a mushroom over a glass which contains it, when, falling upon the surface, they presently subside to the bottom. These spores sometimes merely multiply without any further progress in development; sometimes they proceed a certain way only, and then, the conditions necessary for their further advance failing, this is arrested; sometimes, as in the Sistotrema, the plant appears twice under a perfect form, being for part of its existence a Hydnum, and during the other half a Boletus; but, generally speaking, these minute corpuscular bodies are destined to receive an infinite variety of protean and imperfect forms, and to pass stage by stage, and step by step, to the full attainment of that ultimate one which they assume when their growth has reached its natural limits. Sometimes the spore expands outright into a puff-ball; sometimes it shoots up straight into a club, as in some of the Clavarias; or lies like a bowl, resupinate on the ground and stalkless, as in the Peziza; in other cases, it assumes the more perfect but much less simple forms of Chanterelle, Boletus, Dædalea, Morel, or Mushroom.
Development of Seeds
The mode in which the organs immediately containing the seeds are formed, differs according to the family. In the tribe of puff-balls, where the seed is formed in the interior of the fungus, there is no hymenium; a few of the internal cells (when the Lycoperdon has attained its full size) begin to enlarge, and these in a short time are found to contain small granules, generally of a determinate number, and moistened by a fluid secreted from within the walls. In such funguses as have an hymenium it is only some of the superficial cells, and these in a particular position in reference to the receptacle, that contain seeds; though perfect identity of structure throughout, is evinced in a conclusive manner if we invert the head of a young fungus on its stalk; for then these thecæ begin to form and to fill themselves with seed, not on the side where they were about to do so previous to this inversion of the head, but on that which was the uppermost and sterile surface, and which, now that it is the undermost, has become prolific. The expansion of a fungus, according to Vittadini, is effected as follows:—“These thecæ,” of which we have been speaking, “as they swell, become distended with the contained seed, and mostly so at their free extremity, since they have more room for expansion in that direction than at the other, which is impacted into the substance of the pileus; in consequence of this, a series of wedges are formed which, as the seed continues to distend them, force out the pileus, loosen its marginal connections with the stalk, uncurl its involuted borders, and finally open up its cells, pores, and sinuses.”109
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).