The invisible engine: The hidden power of the fungal mycelium in life and decay

“ If we pluck a flower, in its bosom we see many a charming insect. If we pick up a fallen leaf, there is probably the trace of an insect larvæ hidden in its tissue. The drop of dew upon this leaf will probably contain its animals, visible under the microscope. The very mould which covers our cheese, our bread, our jam, or our ink, and disfigures our damp walls, is nothing but a collection of plants.
The starting point of life is a single cell-that is to say a microscopic sac filled with liquid and granules, and having within it a nucleus, or smaller sac. ”

“ The mycelium, or vegetable part of the fungus, burrows in the tissues of the tree, and often destroys it; the “bracket” represents the fruiting stage, and produces innumerable spores which gain entrance to other trees by some wound or cut surface ”

“ Its spores, like other mushrooms, are shed upon the ground from the white gills beneath, as described in our chapter on "Spore-prints," or wafted to the ends of the earth on the breeze, and eventually, upon having found a suitable habitat, vegetate in the form of webby, white, mould-like growth—mycelium—which threads through the dead leaves, the earth, or decaying wood. This running growth is botanically considered as the true fungus, the final mushroom being the fruit, whose function is the dissemination of the spores. ”

“ Fungi exhibit no separation of root, stem, or leaves, as exists in the higher plants; nor do they contain chlorophyll, the presence of which is so generally associated with the idea of a plant. But they consist of aggregations of mostly elongate cells, forming branched and interlacing colourless fibres, buried like roots in the substance (matrix) upon which they grow, and from which they derive their nourishment; this portion of the Fungus is called the mycélium (μὑκης, a fungus) . The portion of the Fungus projecting beyond the surface of the matrix is the fructification ”

“ Fungi, like other organisms, have two principal things to do—viz., to accumulate energy and to expend it; to grow and to produce fruit. The hyphæ of a fungus are, therefore, in ordinary cases of two sorts—nutrient hyphæ forming the mycelium, and fruiting hyphæ which make up the fructification. In what we term puff-ball, mushroom, we have simply the fructification—the fruiting hyphæ—all compacted together, while the mycelium lies hidden beneath the surface. When, however, we pluck the mushroom from its place, the mycelium may perhaps seldom be discovered. ”

“ But most of the species included in it are either quite invisible, or else the parts which characterize them as fungi are so small as to be indistinguishable. The feature by which a fungus may always be known is the mycelium. Every plant of which this structure forms a part, spreading its web through-out the substance on, or in, which it grows, belongs among fungi. They differ among themselves in such comparatively unimportant respects as the mode of growth of the hymenium, or the degree of complexity of the reproductive system, but mycelia and spore production are their essential characters. ”

“ No one can have observed the mycelium of fungi at work on old stumps, twigs, and decayed wood, without being struck with the rapidity and certainty with which disintegration is being carried on. The gardener casts on one side, in a pile as rubbish, twigs and cuttings from his trees, which are useless to him, but which have all derived much from the soil on which they flourished. Shortly fungi make [223] their appearance in species almost innumerable, sending their subtle threads of mycelium deep into the tissues of the woody substance, and the whole mass teems with new life. ”

“ Fungi live therefore either as parasites or saprophytes, and as the same species may pass part of its life in a living host to occur at another stage of its development as a saprophyte, it is impossible to distinguish definitely between parasitic and saprophytic forms. The vegetative body of a fungus, that is the portion which is concerned with providing nourishment and preparing the plastic food-substance for the reproductive organs, is known as the mycelium. ”

“ Generally, the spawn, or what in scientific language is called the mycelium, is supposed to be analogous to seed, while it really is what may be termed the vegetation of the plant, or something analogous to roots, stems, and leaves of ordinary plants, the visible part or stem, head and gills, of the mushroom being, in fact, the fructification, though in such an apparent preponderance to the other parts. A knowledge of the anatomy and life-history of the mushroom is not necessary to the cultivator, and is not familiar even to those who make of mushrooms a study. ”

“ The paradox of ‘hiddenness’ and ‘radiance’ illustrates the limitations of language in its attempt to describe what is essentially ineffable. It is necessary to ‘transcend’ language by engaging one’s faculty of intuition in order to grasp the hidden meaning of the mystical statement. ”

“ When the spore germinates, it sends out a delicate thread that grows rapidly in length and forms very many branches that soon permeate every part of the substance on which the plant grows (b, Fig. 272) . One of these threads is termed a hypha. All the threads together form the mycelium of the fungus. The mycelium disorganizes the material in which it grows, and thus the mucor plant (Fig. 271) is nourished. It corresponds physiologically to the roots and the stems of other plants.
Fig. 272.—Spores of Mucor, some germinating. ”

“ If there be any exceptions to the law that parasites select for their sustenance the subjects of debility and decay, such exceptions are rarely to be found among the vegetations belonging to fungi, which invariably derive nutrition from matter in a state of lowered vitality, passing into degeneration, or wherein decomposition has already taken place to a certain extent.... ”

“ Modern science does not hesitate a moment between these alternatives. Physiology writes over the portals of life,
“Debemur morti nos nostraque,” with a profounder meaning than the Roman poet attached to that melancholy line. Under whatever disguise it takes refuge, whether fungus or oak, worm or man, the living protoplasm not only ultimately dies and is resolved into its mineral and lifeless constituents, but is always dying, and, strange as the paradox may sound, could not live unless it died. ”

“ As o'er the brow the transient shade Of thought, the hues of fancy flit away:— Yet in the mystic womb unseen, Of the dark ruling hours that sway Our mortal lot, whate'er has been, With new creative germ defies decay. The blooming field is time For nature's ever-teeming shoot, And all is seed, and all is fruit. ”

“ The term fungus, or more often its plural form fungi, denotes a most persistent, industrious class of plants whose one aim in life is the production of millions and millions of spores. The sage-green spots on the neck of my onion were the spores of a fungus. With a needle I could scatter them like a cloud of fine powder. But I could not see how they were growing on the little plants without a microscope that would magnify them about three hundred times.
With such a microscope I saw transparent, branching, interlacing threads, called hyphæ, and thousands of loose spores. ”

“ In old mycelium, and also in the sporangia-bearers, the contents of which are mostly used for the formation of spores, and the substratum of which is exhausted for our fungus, short stationary pieces, filled with protoplasm, are very often formed into cells through partitions in order to produce spores, that is, grow to a new fruitful mycelium. ”

“ Let us quit the infusoria and glance with our microscopic eye at some other marvellous objects belonging to the invisible world. If we look through our magic tube at the downy mould formed upon any decaying substance, a wonderful forest of delicate thread-like plants will be revealed. These beautiful fungi will be seen to multiply and grow, to swell and finally to burst, scattering their invisible spores into the surrounding air.
If we make use of our microscope to examine the eggs of insects we shall have cause to wonder at their elaborate carving and beautiful forms. ”

“ When the rest-spores are mature, they separate themselves from the mycelium on which they grow, and lie as free bodies in the substance of the potato. And when in course of time the whole of the plant perishes, these small hardy bodies remain, able to endure through the winter, and ready to renew the life of the destructive fungus with the restored vegetable life of another year. ”

“ Finally, it is a great characteristic of fungi in general that they are very rapid in growth, and rapid in decay. In a night a puffball will grow prodigiously, and in the same short period a mass of paste may be covered with mould. In a few hours a gelatinous mass of Reticularia will pass into a bladder of dust, or a Coprinus will be dripping into decay. Remembering this, mycophagists will take note that a fleshy fungus which may be good eating at noon may undergo such changes in a few hours as to be anything but good eating at night. ”

“ Some of the woods have compounds in their cells easily induced to decompose and start the wood-tissue, while others have different compounds requiring inducing agents of greater intensities to begin decay; and it is not true that a fungus which will destroy one wood will destroy all of the other species, and this one fact is of great practical importance, for, in a road-bed filled with the mycelium of one kind of decayed wood, another wood may be used which is not affected by that fungus, and its mycelium would be inert. ”

“ They are light as vapor and abound in air, in water, in dust, in sand, ready, when warmth and moisture favor, to burst into life. As has been said, the dry-rot fungi flourish upon the products of wet-rot. Different stages of decay produce food of different qualities, adapted to different species of fungi. One species takes up the process where another leaves it, and carries it further and further forward. ”

“ It may seem a small thing to admit that the dull vital actions of a fungus, or a foraminifer, are the properties of their protoplasm, and are the direct results of the nature of the matter of which they are composed. ”

“ We may allude, in passing, to another phase of destructiveness in the mycelium of fungi, which traverse the soil and interfere most injuriously with the growth of shrubs and trees. The reader of journals devoted to horticulture will not fail to notice the constant appeals for advice to stop the work of fungi in the soil, which sometimes threatens vines, at others conifers, and at others rhododendrons. Dead leaves, and other vegetable substances, not thoroughly and completely decayed, are almost sure to introduce this unwelcome element. ”

“ Putting everything together, it is not difficult to explain the symptoms of the disease. The struggle between the mycelium on the one hand, which tries to extend all round in the cortex, and the tree itself, on the other, as it tries to repair the mischief, will end in the triumph of the fungus as soon as its ravages extend so far as to cut off the water supply to the parts above: this will occur as soon as the mycelium extends all round the cortex, or even sooner if the effusion of turpentine hastens the blocking up of the channels. ”

“ Erysipha ́les, an important family of ascomycetous Fungi, distinguished by the presence of typical sexual organs and closed ascus-fruits (cleistocarps) which bear characteristic appendages concerned with dispersal; also by the fact that each segment of the septate mycelium contains a single nucleus. They are all parasites, appearing on leaves, stems, or fruits as white patches of mycelium ('mildew') . During summer innumerable conidia are produced, which spread the disease rapidly; in autumn the black ascus-fruits develop and carry the fungus through the winter. ”

“ Maudsley will not deny that the discovery of the one true cause of the disease puts us in an infinitely better position for circumscribing its ravages, for preventing it, ay, and for curing it than we were before. We know now that it is the outgrowth not of any subtle tendency passed on from generation to generation, but of a fungus which invades the body from without, by certain channels and has a definite life history ”

“ Go and tell your great Council of this death that we have created for every planet that will not obey us.
"We have gone back into the history of dealing death and have come back with a death such as the Universe has never known before!
"Here is a rapacious, deadly fungus we have been two centuries in developing. The spores contained in that tiny metal tube would be invisible to the naked eye—and yet given but a little time to grow, with air and vegetation and flesh to feed upon, and even that small capsule would wipe out a world. ”

“ Turn now from outward events to inner life; from events grown shadowy with time, to life ever dim and mysterious alike to savage and sage. Everywhere man beholds much that is incomprehensible; within, around, the past, the future. Invisible forces are at work, invisible agencies play upon his destiny. And in the creations of fancy, which of necessity grow out of the influence of nature upon the imagination, it is not strange that mysteries darken, facts and fancies blend ”