This section is from the book "A Library Of Wonders And Curiosities Found In Nature And Art, Science And Literature", by I. Platt. Also available from Amazon: A library of wonders and curiosities.
The organization (says M. de Jussieu) which distinguishes plants and other productions of nature, is visible in the fungi, and the particular organization of each species is constant at all times, and in all places; a circumstance which could not happen, if there were not an animal reproduction of species, and consequently a multiplication and propagation by seed. This is not, he says, an imaginary supposition, for the seeds may be felt like meal upon mushrooms with gills, especially when they begin to decay; they may be seen with a magnifying glass, in those that have gills with black margins: and, lastly, says he, botanists can have no doubt that fungi are a distinct class of plants; because, by comparing the observations made in different countries, with the figures and descriptions of such as have been engraved, the same genera and the same species are every where found.
Notwithstanding this refutation by M. de Jussieu, another naturalist, M. de Necker, has lately maintained, in his My-citologia, That the fungi ought to be excluded from the three kingdoms of nature, and be considered as intermediate beings. He has observed, like Marsigli, the matrix of the fungi; and has substituted the word carchte (initium faciens) instead of situs; imagining that the rudiment of the fungus cannot exist beyond that point in which the development of the filaments of fibrous roots is perceived. He allows, that fungi are nourished and grow like vegetables; but he thinks that they differ very much from them in respect of their origin, structure, nutrition, and rapidity of growth. He says, that the various vessels which compose the organization of vegetables, are not to be found in the fungi, and that they seem entirely composed of cellular substance and bark; so that this simple organization is nothing more than an aggregation of vessels endowed with a common nature, that suck up the moisture in the manner of a sponge; with this difference, that the moisture is assimilated into a part of the fungus, and not merely imbibed for nutrition.
Lastly, That the fructification, the only essential part of a vegetable, and which distinguishes it from all other organized bodies, being wanting, fungi cannot be considered as plants. This, he thinks, is confirmed by the constant observation of those people who gather the morelle and the mushroom, and who never find them in the same spots where they had formerly grown. As the generation of fungi (says M. Necker) is always performed when the parenchymatous cellular sub stance has changed its nature, form, and function, we must conclude that it is the degeneration of that part which produces these bodies.
But if fungi were owing merely to the degeneration of plants, they would be still better entitled to constitute a new kingdom. They would then be a decomposition, not a new formation, or new bodies. Besides, we cannot deny, that in those bodies which form the limit between the animal and vegetable kingdoms, the organization becomes simple, as the organs destined for nutrition are multiplied; but, as the last in the class of insects belongs to the animal kingdom, fungi ought, notwithstanding the simplicity of their organization, still to belong to the vegetable kingdom.
The parenchymatous, or cellular substance, which, as M. Bonnet says, is universally extended, embraces the whole fibrous system, and becomes the principal instrument of growth, must naturally be more abundant in those produc tions; and this accounts for the rapidity of their enlargement. Besides, growth, whether slow or rapid, never was employed to determine the presence or absence of the vegetable or animal character. The draba verma, which, in a few weeks, shoots, and puts forth its leaves, flowers, and fruit, is not less a plant than the palm. The insect that exists but for a day, is as much an animal, as the elephant that lives for centuries. As to the seeds of the fungi, it is probable that nature meant to withdraw from our eyes the dissemination of these plants, by making the seeds almost imperceptible; and it is likewise probable, that naturalists have seen nothing but their capsules. Since, however, from the imperfection of our senses, we are unable to perceive these seeds, because those bodies which have been called their seeds, and the fragments or cuttings of the plants themselves, have not produced others of the same species; Nature seems to have reserved for herself the care of disseminating certain plants: it is in vain, for instance, that the botanist sows the dust found in the capsules of the orchis, though every one allows it to be the seed.
But, after all, what are those parts in the fungi casually observed by naturalists, and which they have taken for the parts of fructification? These are quite distinct from the other parts; and whatever may be their use, they cannot have been formed by the prolongation of the cellular substance, or of the fibres of the tree on which the fungus grows: they are, therefore, owing, like flower and fruit, to the proper organization of the plant. The plants, however, have a particular existence, independent of their putrefying nidus. The gills of certain fungi, which differ essentially from the rest of the plant in their conformation, would be sufficient to authorize this latter opinion. But can putrefaction create an organic substance? Nature undoubtedly disseminates through the air, and over the surface of the earth, innumerable seeds of fungi, as well as eggs of insects. The plant and the animal are excluded, when the nidus, in which they are deposited, or the temperature, is favourable for their development. No fortuitous concourse, either of atoms or fluids, could produce bodies so exquisitely and so regularly organized. It is suf-ficient, to throw one's eye on the beautiful plates which Schoeffer has published of them, and compare them, by the glass, with the warts and other excrescences of animals, to be convinced that they have not the same origin. The function of the cellular substance in vegetables must be greatly superior to that in animals, if it could produce any tiling but deformities. The greater part of fungi exhibit a configuration much too regular, constant, and uniform, to be the effect of chance or putrefaction. As this form is preserved the same in all places where fungi have been found, it follows, that they contain in themselves the principles of reproduction. They resemble the misletoe, and other parasitic plants, which are perfectly distinct from the trees on which they grow. The fungi, therefore, are organized and living substances, - or true plants.