Rust fungus

“ They may attack leather, cloth, etc., in a damp house. Other allied forms may do damage to living plants. Some of these live upon the lilac, rose, or willow. These fungi do not penetrate the host plant to any depth, for they obtain their food from the outer layer of cells in the leaf of their host and cover the leaves with the whitish threads of the mycelium. Hence they may be killed by means of applications of some fungus-killing fluid, as Bordeaux mixture. ”

“ One of these forms of dry rot fungus is Merulius lacrymans, which is sometimes spoken of as if it were the only one, though perhaps the most destructive in houses. Another is Polyporus hybridus, which attacks oak-built vessels; [X] and these are not the only ones which are capable of mischief. It appears that the dry rot fungus acts indirectly on the wood, whose cells are saturated with its juice, and in consequence lose their lignine and cellulose, though their walls suffer no corrosion. ”

“ It is known, too, that however much the fungus is found within the tissues of the host-plant, it began its growth outside of the latter, and gained introduction only by forcible entrance. Spores are never taken up by absorption and carried by the aqueous currents from part to part of the plant. The fungus passes through the tissues very much as roots pass through soil, sometimes apparently without in any degree successful opposition, sometimes nearly or quite baffled in the struggle by the mechanical and physiological resistances of the host-plant. ”

“ Whatever, therefore, may be the appearance or situation of the fungus producing the dry rot, or from whatever substance it originates, that substance must be in a corrupt state.
Fungi result from, or are attendant on, vegetable corruption, assisted by an adequate proportion of heat and moisture. The sap, or principle of vegetation, brought into activity, is, according to the ‘Quarterly Review,’ No. 15, the cause of dry rot, in as far as it is favourable to the growth of fungi, as it would seem to be when in a state of fermentation.
Vegetable corruption invariably presupposes fermentation. ”

“ There is no cargo, even that which is shipped in tolerably dry condition, in which, upon its arriving here, may not be found some deals, with the fungus beginning to vegetate on their surface. If they are deals that have been floated down the rivers of America or Canada, and shipped in a wet state, on their arrival here they are so covered with this network of the fungus, that force is often necessary to separate one deal from another, so strongly does the fungus occasion them to adhere. ”

“ Both air and dampness are essential to the growth of fungus. That is the reason why timbers deep beneath ground or water do not decay. Air is absent, though moisture is abundant; while in the dry Egyptian tombs, air is abundant but moisture is wanting, fungus cannot exist, and consequently decay of the wood does not occur. Nothing is needed to render timber immune to decay except to keep fungus out of the cells. Some of the fungus concerned in wood rotting is microscopic, while other appears in forms and sizes easily seen and recognized. ”

“ Unfortunately this destructive power of fungi over vegetable tissues is too often exemplified in a manner which man does not approve. The dry rot is a name which has been given to the ravages of more than one species of fungus which flourishes at the expense of the timber it destroys. ”

“ 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. ”

“ Experiments in these varieties of fungi are highly dangerous, as many of the most poisonous so closely resemble the edible species that they can with difficulty be distinguished. There is one kind of fungus that I have met with in the forests which, from its offensive odor and disgusting appearance, should be something superlatively bad. It grows about four inches high; the top is round, with a fleshy and inflamed appearance; the stalk is out of all proportion in its thickness, being about two inches in diameter and of a livid white color ”

“ That we may better understand the structure of the disease-causing fungi we are about to examine, let us refresh our memories concerning that very common fungus, known as white mould and mentioned in an earlier chapter. The reason fungi cause damage to other plants, the one invariable reason, is that they, being unable to manufacture food for themselves, steal it from the plants on which they grow. Some of them are parasites and steal their food from living animals or plants; others live upon dead animal or vegetable matter and the white mould is one of the latter fungi. ”

“ By carefully removing the bark from a root thus invaded the fungus is seen in the form of a dense, nearly white, mass of mycelium, which, as the parts around decay, gradually produces again the rhizomorphs already described. These rhizomorphs are a characteristic part of the fungus. Occurring both in the decayed wood from which they spread to the adjacent parts, and extending in the soil from root to root, they constitute a most effective agency in the extension of the disease. ”

“ In timber of moderate length the fungus becomes larger and more destructive, in consequence of the matter congenial to its growth affording a more plentiful supply.
It is a great characteristic of fungi in general that they are very rapid in growth, and rapid in decay. In a night a puff-ball 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. Many instances have been recorded of the rapidity of growth in fungi ”

“ A second aspect is the direct encouragement of special components of the fungus flora for particular purposes by selective feeding. Thus, in a laboratory experiment, McBeth and Scales [43] record an increase of 2000 times in cellulose-destroying and other soil fungi by this method. It has been pointed out that soil fungus activities such as ammonification, proteolysis and carbohydrate decomposition are controlled by factorial equilibria, and for special purposes it would seem feasible to weight the balance so that particular activities may be favoured. ”

“ It is these tubes, and the spores thrown from them, which you see forming a kind of halo round the dead fly as it clings to the pane. Other fungi in the same way kill the silkworm and the caterpillars of the cabbage butterfly. Nor is it only the lower animals which suffer. When we once realise that fungus spores are floating everywhere in the air, we can understand how the terrible microscopic fungi called bacteria will settle on an open wound and cause it to fester if it is not properly dressed. ”

“ With many of the fungi in the soil the roots of plants have to compete—just as plant competes with plant—for water, salts, and other food-materials. The toadstools which are so conspicuous in fields and forests spring from mycelia which ramify in the ground, and are busily breaking down the remains of other organisms, and just such fungi are known to store up relatively large quantities of salts of potassium and phosphorus—the very salts which are so valuable to crops and occur so sparingly in most soils, but which the extensively spread fungus mycelia can gradually accumulate. ”

“ Although rather a common easily recognisable and aesthetically pleasing fungus growing in its characteristic clusters at the base of trees, it is a weak parasite entering the living tissue after invading decayed areas of the tree. This is the reason why when branches are broken off trees by wind, snow or storms, they should be carefully trimmed to remove ragged edges and the wound treated with a protective tar to stop the entry of rain, cold and fungus spores. Other more destructive fungi may enter a tree through such wounds ”

“ The parasitism of numerous minute species on living and growing plants has its parallel even amongst phanerogams in the mistletoe and broom-rape and similar species. Amongst fungi a large number are thus parasitic, distorting, and in many cases ultimately destroying, their host, burrowing within the tissues, and causing rust and smut in corn and grasses, or even more destructive and injurious in such moulds as those of the potato disease and its allies. A still larger number of fungi are developed from decayed or decaying vegetable matter. ”

“ As atmospheric dust is filled with the spores of fungi, they may be conveyed by rain into the earth, absorbed by the roots of vegetables, and diffused with the sap throughout the whole plant. There are numerous species of dry-rot fungi adapted to different conditions of life and presenting different aspects. Nor are they restricted to timber. They may flourish in the earth, where they present a perfectly white mycelium, branching and interlacing like roots; and when workmen are employed on grounds which are affected by the dry-rot fungi their health is often disturbed. ”

“ It would be impossible here to give details of the destructive powers of the microscopic fungi. They permeate almost everything that is capable of undergoing change; and while they often are beneficial scavengers, they are also very destructive. Dry rot in wood and timber is the work of fungi. They traverse the soil and arrest the growth of vegetation ”

“ 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. ”

“ Though the growth of fungi undoubtedly accelerates the progress of dry rot, it would seem that the true origin of the disease is the incipient decomposition of the sap in wood, and that by virtue of this decomposition the fungi obtain a nidus for their growth. The most formidable of the dry rot fungi is the species Merulius lacrymans, which is particularly destructive of coniferous wood ”

“ Relation of Soil Fungi to Living Plants.
Older classifications of fungi frequently divided these organisms into four categories—parasites, saprophytes, facultative parasites, and facultative saprophytes, but the further mycological studies are carried the more clearly it is seen that these groups are entirely artificial. There are probably few fungi that cannot, under particular conditions, invade living tissues, and it only seems a question of time before at all events the vast majority of fungi will be grown on synthetic media in the laboratory. ”

“ On older trees still than these, huge lobes of fungi grew like lungs. Here, as everywhere, the Unfulfilled Intention, which makes life what it is, was as obvious as it could be among the depraved crowds of a city slum. ”

“ Every part of nature teaches that the passing away of one life is the making room for another. The oak dies down to the ground, leaving within its rind a rich virgin mould which will impart a vigorous life to an infant forest. The pine leaves a sandy and sterile soil, the harder woods, a strong and fruitful mould. So this constant abrasion and decay of our lives makes the soil of our future growth. The wood we now mature, when it becomes mould, determines the character of our second growth. ”

“ The sky, which a moment since was bright as burnished gold, has already changed to a dusky grey, with here and there streaks of purple hue. A solitary bird, truant to its mate, or perhaps a mourner for its loss during the day's excursion, is seen like a wayfarer, with tired flight, wearily labouring to reach the wood ere nightfall. ”

“ Nature, now, had awakened in her that morbid tenderness, that eagerness for the caress of the other sex; so, as she approached the open casement and saw the youth so full of manly vigour, convulsed—as he was—by lust, and burning to quench the fire that was consuming him, she felt irresistibly drawn towards him; she was in fact like a withering plant, which—fading under the rays of a scorching sun—droops towards the earth as if to breathe the moist vapours that arise from the soil. ”

“ Nature strews her nuts and flowers broadcast, and never collects them into heaps. This was the soil it grew in, and this the hour it bloomed in; if sun, wind, and rain came here to cherish and expand the flower, shall not we come here to pluck it? ”

“ when it is older, it has filaments and fibres like hemp and flax. Nettle cloth is as good as linen cloth. Chopped up, nettles are good for poultry; pounded, they are good for horned cattle. The seed of the nettle, mixed with fodder, gives gloss to the hair of animals; the root, mixed with salt, produces a beautiful yellow coloring-matter. Moreover, it is an excellent hay, which can be cut twice. And what is required for the nettle? A little soil, no care, no culture. Only the seed falls as it is ripe, and it is difficult to collect it. That is all. ”