Dacryomyces: the folded, gelatinous, Tremella-like fruit-bodies break out in winter on dried wood (hedges) in the form of red or yellow drops. D. deliquescens is very common (Fig. 121). The following genera have cartilaginous fruit-bodies.—Calocera (Fig. 162), with club-like, simple, or branched, Clavaria-like, fruit-bodies; the orange coloured fruit-bodies of C. viscosa grow aggregated together on the wood of Conifers.—Guepinia resembles a Peziza, and has the hymenium only on the hollow upper surface.—Dacryomitra resembles a Mitrula (Fig. 162).
Family 2. Hymenomycetes.
This family is very rich in species (more than 8000 have been described), and to it belong all the “Mushrooms” and “Toadstools.” The fruit-bodies present very various forms; they are generally fleshy, very perishable, seldom leathery or corky, in the last case often perennial. The basidia are more or less cylindrical and bear generally 4 (seldom 2, 6 or 8) sterigmata and basidiospores. The hymenium in the fully-formed fruit-bodies lies free on the surface: in orders 1 and 2 and a portion of order 6 it is from the commencement exposed, fruit-bodies gymnocarpic; orders 3–6 have hemiangiocarpic fruit-bodies (p. 157). In the first order the basidia (or the hymenium) are developed immediately from the mycelium (Fig. 163); the fruit-bodies of orders 2 and 3 present a higher grade of development, and have between the mycelium and hymenium a special hyphal-tissue, a stroma, which is crustaceous, club-like, or coralloid, etc., and in general bears the hymenium on the largest part of the free, smooth surface. In the forms most highly developed (orders 4–6) a new tissue—the hymenophore—is introduced between the stroma and hymenium, which appears on the under side of the fruit-body in the form of warts, projections, tubes, folds or lamellæ (Figs. 166, 167, 174 bc). Paraphyses are frequently found in the hymenium, among the basidia. In the Hymenomycetes few examples of conidia can be recognised at first. More frequently chlamydospores are found, particularly oidia. The mycelium is richly branched, generally colourless, often perennial; it lives in humus or decaying wood, and is seldom parasitic. The hyphæ generally have clamp-connections and unite, sometimes, to form a rhizomorpha (Fig. 177) or sclerotia with coloured, pseudo-parenchymatous covering.
Fig. 163.—Exobasidium vaccinii. I Hypertrophied stem of Vaccinium vitis idæa; II leaf with gall-like swelling; III section of II; IV transverse section: m mycelium between the parenchymatous cells; p hypodermal cells; e epidermis with basidia in various stages of development; V epidermis with germinating spores; VI and VII spores germinating in water (IV-VII × 620).
Order 1. Tomentellaceæ. To this order belong the simplest of the Hymenomycetes. The basidia (Fig. 145) arise free and irregularly from the mycelium; a hymenium is entirely absent or very slightly formed (in Corticium it attains its highest development); fruit-bodies are also wanting.—In general they form flaky, membranous or leathery coverings on bark and wood. Some are parasites.
Hypochnus without conidia.—Tomentella with conidiophores; growing on wood or earth.—Exobasidium vaccinii (Fig. 163), a parasite on Vaccinium, Andromeda, Arctostaphylos, and Rhododendron, forms flaky-powdery, white or red coverings and may cause hypertrophy of the parts attacked. E. warmingii is parasitic on Saxifraga; E. lauri causes outgrowths on the stem of Laurus canariensis as long as a finger, which formerly were regarded as aerial roots.—Corticium forms membranous to leathery layers or crusts; C. quercinum on wood and bark, particularly Oak, is flesh-coloured; C. cæruleum has a blue hymenium; C. giganteum on the bark of fallen Pine-trees.
Order 2. Clavariaceæ. The hymenium is situated on a stroma, and either completely covers the smooth surface of the more or less fleshy gymnocarpic fruit-body, or is confined to a tolerably well defined upper portion of it (Typhula). Paraphyses absent. The vertical, white, yellow, or red fruit-bodies are roundish or club-like, undivided or richly branched (Fig. 125). Generally on the ground in woods, seldom on tree-stems, etc.
Fig. 164.—Clavaria coralloides (nat. size).
Genera: Clavaria, generally large Fungi with thick, round branches. C. botrytis has a very thick, tubercular stem with numerous short, flesh-coloured branches: it has an agreeable taste. C. coralloides has a brittle, richly-branched fruit-body (Fig. 164); basidia with two large spores. C. pistillaris consists of a single, undivided club of a yellowish-white colour.—Sparassis has compressed, leaf-like, curled branches; S. crispa has fruit-bodies as large as a white cabbage-head, with an agreeable taste.—Typhula and Pistillaria are small Fungi with filamentous stalks, terminating in a small club. The fruit-bodies of the former often arise from a small, spheroid sclerotium; the latter is distinguished by the basidia bearing only two spores.
Order 3. Thelephoraceæ. The hymenium is placed on a stroma and covers the smooth surface of the leathery hemiangiocarpic fruit-body, generally on its under side. The edge of the stroma, which bounds the hymenium, is sometimes especially developed (Stereum). Saprophytes.
Genera: Thelephora. The fruit-bodies in this genus are brown, very irregularly shaped, and often lobed. The spores too are brown, but in the other genera colourless. The species are found growing on barren soil. T. laciniata (Fig. 165) has imbricate, semicircular, dark-brown pileus, which is jagged at the edge and upper surface. The fruit-bodies are very often raised above the ground, and although this species is not a parasite, yet it destroys young seedlings by growing above and smothering them.—Stereum has a stiffer fruit-body, with a distinct, fibrous, intermediate layer. It grows on bark and wood, projecting like a series of imbricate brackets. S. hirsutum is yellow; its free edge is provided with a number of stiff hairs, the upper surface being divided into a number of zones. S. purpureum has a red-violet hymenium which distinguishes it from the previous species.—Cyphella has a membranous cup- or bell-shaped fruit-body, often borne on a stalk, the concave surface being covered with the hymenium. They are small, white Fungi, growing on Moss and dead stems.—Solenia is closely related to Cyphella; its fruit-bodies are smaller and hairy; they are found clustered together forming a crust-like covering on dead wood.—Craterellus has a large, funnel-shaped fruit-body, the hymenium covering the external surface. C. cornucopioides is shaped like a trumpet or a “horn of plenty.” It is dark-grey, several inches in height, and grows gregariously on the ground in forests. It is distinguished by the basidia bearing only two sterigmata.
Fig. 165.—Thelephora laciniata (nat. size).
Order 4. Hydnaceæ. The fruit-body is most frequently fleshy, and varies considerably in shape, the simplest forms being resupinate,[14] the higher ones umbrella-like. The hymenophore is found on the free or downward-turned surface, and always takes the form of soft emergences hanging vertically downwards. The emergencies may be thorn-, awl-, or wart-like. The species are found growing on the soil and on dead wood.
Genera: Hydnum has subulate, distinct emergences. H. repandum is yellow, the stalk being placed in the centre of the pileus. It is an edible species, and often forms “fairy rings” in woods. H. auriscalpium (Fig. 166) is dark-brown, with stalk placed at the edge of the pileus. It grows on old Fir-cones. H. erinaceus grows on old tree-trunks. The fruit-body is yellow and very large—as big as a human head—with emergences as much as an inch in length.—Irpex has a leathery fruit-body, partly resupinate, partly with free, projecting edge; the under side bears tooth-like emergences which are arranged in rows, and Irpex thus forms a transition to the Agaricaceæ.—Phlebia is entirely resupinate, with radially-arranged folds on the free side, and pectinate border.
Fig. 166.—Hydnum auriscalpium, upon a Fir-cone, in different stages of development.
Order 5. Polyporaceæ (Pore-Fungi). An order very rich in species (about 2000 species are described). The fruit-body is of very different forms—resupinate, projecting like a bracket, hoof-like, or umbrella-shaped. In some it is fleshy and edible, in others leathery or corky, persisting for several years. The hymenophore is situated on the under side of the fruit-body, and consists of wide or narrow tubes or pores, whose inner surface is clothed with the hymenium (Fig. 167). In some fruit-bodies large cavities are to be found, which have arisen as interstices between the labyrinthine curved and reticulate folds. Chlamydospores are known in some species. Conidia occur very rarely. Many species work considerable damage: some as parasites on trees, others by destroying timber.
Fig. 167.—Polyporus igniarius. Section through the under side of the Fungus: h-h is hyphal-tissue between the tubes, formed by irregularly felted hyphæ, many of which are seen cut across; s is the hymenium which covers the walls of the tubes, and from which the basidia with the spores protrude.
Genera. Polyporus (Pore-Fungus). The tubes are narrow, accurately fitted together, and forming a thick layer on the under side of the fruit-body, appearing as a number of fine holes. The fruit-body most frequently resembles a bracket, or is hoof-shaped, with one side growing from a tree-trunk; it is very often perennial, and a new layer of tubes arises in each succeeding period of vegetation. Strata, corresponding to the periodically interrupted growth, are thus formed in storeys one above the other, and are visible on the upper surface of the fruit-body, as well as in the interior, as a series of concentric belts, sometimes as many as half a score or more in number. P. fomentarius (Touchwood) attacks trees, especially the Beech. The spores germinate on wounds from broken branches, and the hyphæ, following the course of the medullary rays, find their way into the interior of the tree, from whence the mycelium spreads upwards, downwards, and peripherally, so that the wood becomes rotten (“white-rot”) and thick felts of mycelium are formed in radial and tangential directions. A dark line, caused by the youngest parts of the hyphæ containing a brown juice, marks the boundary between the rotten and the unattacked parts of the stem (Fig. 168); at places where the mycelium extends to the bark, the cambium becomes destroyed and further growth is arrested, so that longitudinal furrows arise on the stem. It is at these places, too, that the hoof-shaped, ash-coloured fruit-bodies are developed, which may attain a circumference of upwards of 7 feet. The interior of the fruit-body consists of a dried-up, loosely felted, red-brown mass of hyphæ, which has been used for tinder and as a styptic (“Fungus chirurgorum”). P. igniarius has a harder, dark-brown, more rounded fruit-body; it grows in a similar manner, but especially attacks Oaks, Poplars, and Plum-trees, the wood of which becomes rotten, and is called touchwood. P. pini (Trametes pini), (Fig. 170), a parasite on the stems of Pinus, causes a kind of “red-rot” in the stem. P. sulphureus has a soft, cheesy, yellow fruit-body; it produces “rot” in Oaks and Apple-trees. P. officinalis, Larch-fungus (“Fungus Laricis” in Pharmocopœia), grows on Larch-trees in the south-east of Europe. P. versicolor has thin, semicircular fruit-bodies, with zones of various colours on the upper side; it is one of the most frequent species on tree-stems. P. frondosus grows on soil in woods, and consists of numerous aggregated fruit-bodies, which become very large and fleshy. This species is edible. P. perennis also grows on the soil in woods; it is very leathery, with central stalk, and has concentric zones on the upper surface of the fruit-body. P. vaporarius destroys the wood of living Pines (Pinus silvestris) and Firs (Picea excelsa), causing it to become red-brown; in timber this Fungus causes “red-strip” followed by a “dry-rot.” P. squamosus destroys many Walnut-trees, and is also very destructive to Limes and Elms. P. fulvus causes a “white-rot” in Abies alba.
Fig. 168.—Section of stem of a Beech attacked by P. fomentarius: a non-attacked parts of the stem; b the furrows where the mycelium has reached the bark, and where the thick mycelium-strands reach the exterior (⅙th of the nat. size).
Fig. 169.—Base of a Fir-tree, with a number of fruit-bodies of Heterobasidion annosum just beneath the surface of the soil, indicated by the dotted line (¼th nat. size).
Fig. 170.—A fully developed fruit-body of Polyporus pini (Trametes pini), lateral view (nat. size).
Heterobasidion annosum (Polyporus annosus, Trametes radiciperda, Fig. 169) is characterized by its Aspergillus-like conidiophores. It is a parasite on the Pine, Fir, Birch, Beech, etc., and is the chief cause of a root-disease (red-rot) in Pines and Firs; the fruit-bodies develope a large number of basidiospores; they may be very large and are found just beneath the surface of the soil (on living or dead roots), and exposed to the air (on felled stems and roots, in Scandinavia).
Ptychogaster has cushion-like fruit-bodies, which consist chiefly of chlamydospore-chains, formed of ellipsoidal spores, which alternate with short hyphæ having transverse septa and clamp-connections. The hymenial portion is limited to a small group of tubes. Pt. albus (Oligorus ustilaginoides) grows on stumps of Conifers and forms irregular cushions, at first white and later on brown, which consist almost entirely of chlamydospores.
Boletus (Fig. 171) has a fleshy fruit-body resembling a common Mushroom, with central stalk. The layer of tubes is easily detached from the pileus, and the tubes are easily separable from one another. They grow on the ground in woods. Edible species are: B. edulis, with thick, reticulate stalk; B. scaber, with thin stalk and rough pileus; B. luteus, with a ring on the stalk. B. luridus is poisonous, its tubes have red openings, and the flesh turns quickly blue when broken and exposed to the air.
Fistulina hepatica (Beef-steak Fungus), has a red, fleshy, edible fruit-body, with red juice. The tubes are individually distinct; conidia are also developed. Grows on old Oaks.
Merulius lacrymans (“Dry-rot”) has a resupinate fruit-body with white, cotton-like border, and the remaining portions covered by reticulate, ramified veins of a rust-brown colour. In favourable vegetative conditions it is fleshy and exudes large drops of water—hence its specific name and also the name “Tear Fungus.” The mycelium is at first colourless, and then yellow-brown; when dry it is tough and leathery. It destroys the timber in damp houses, extends far and wide over boards and beams and even over the masonry, giving rise to a disagreeable smell in the rooms in which it lodges. In woods the Fungus lives on Pine-stems. It is brought from the forest on the logs of timber, and is distributed from log to log by the mycelium and the basidiospores. The living mycelium can be recognised by the clamp-connections shooting out branches. The basidiospores are often ejected a distance of a metre; they are elliptical (10–11µ long and 5–6µ broad), and germinate easily on damp wood, or in fruit-juice which has been neutralized with urine or alkaline carbonates.
Dædalea (Labyrinth Fungus), has bracket-like, corky fruit-bodies with irregularly-folded plates or discs on the under side. It forms a transition to the Agaricaceæ. D. quercina is frequent on Oak-stumps.
Fig. 171.—Boletus edulis (about ¼th): b longitudinal section of a portion of the pileus.
Order 6. Agaricaceæ (Mushrooms, Toadstools). The hymenophore consists of knife-like plates (lamellæ, gills), which are situated on the under side of the umbrella-like pileus of the fruit-body, and radiate from the central stalk. Those which are first formed extend from the edge of the pileus to the stalk; those formed later reach only a longer or shorter portion of this distance, according to their age. In structure the lamellæ (Fig. 174) consist of a central mass of hyphæ, the trama, continuous with the hyphæ of the pileus; these terminate in a layer of shorter cells, the subhymenial layer, immediately beneath the hymenium which is composed of basidia and paraphyses. In a few species, but not in the majority, the lamellæ are branched, and in some they are decurrent. A few have the stalk placed excentrically, or it may be entirely absent.
Fig. 172.—Development of Psalliota campestris: a, b, c, d show the various stages of the development of the fruit-bodies and the mycelium (m) (nat. size); e the fruit-body in a somewhat later stage, slightly magnified; f longitudinal section of e; n first formation of the hymenium; g longitudinal section of a more advanced fruit-body (nat. size); n the hymenium; o velum partiale (see Fig. 133.)
In the early stages of its development the fruit-body is more or less enclosed in a hyphal tissue—the “veil” (velum universale, or volva). The veil at first completely encloses the young fruit-body, but is afterwards ruptured as the latter grows, part remaining at the base of the stalk as the “sheath” (annulus inferus), and part on the pileus as scales or warts. In the “Fly Mushroom” (Amanita muscaria) the remains of the veil are especially conspicuous as white patches on the bright red ground of the upper surface of the pileus, and as a sheath at the base of the stalk (Fig. 178 v.). Another veil—the velum partiale—a hyphal tissue (Figs. 178 a; 173) stretches from the edge of the pileus to the stalk, and encloses the lamellæ. This veil is ruptured as the pileus expands, a portion attached to the stalk remaining as the “upper ring” (annulus superus) (Figs. 173, 178 a), or a part attached to the pileus hanging down as a fringe round its edge.—Some genera have no veil, the under side of the pileus being exposed from the first (gymnocarpic Agaricaceæ). Those which have a veil (hemiangiocarpic A.) afford a transition to the angiocarpic Gasteromycetes.
Fig. 173.—The cultivated Mushroom (Psalliota campestris).
The mycelium mostly grows in soils rich in humus or dung, on decaying trees and similar objects. Many species, e.g. Tricholoma personatum and Marasmius oreades, form the so-called “fairy rings.” The fruit-bodies in these species are confined to a larger or smaller surface on which they are very regularly arranged in a ring. The reason for this is found in the radial growth of the mycelium, so that the oldest portion, or the starting point, is found at the centre of the ring, and the younger ones, on which the fruit-bodies are formed, at the circumference. The older hyphæ gradually die, and at the same time, the radial growth continuing, the ring of fruit-bodies becomes larger and larger. The “fairy-rings” are marked not only by the fruit-bodies, but also by the more vigorous growth and darker colour of the grass upon these spots.
Some species are parasites. An example is presented by Armillaria mellea, a remarkable and very destructive Fungus in woods and forests (Figs. 176, 177). In addition to the filamentous, white mycelium, it has also black, or black-brown, horny, root-like mycelium-strands (rhizomorpha) which were formerly considered to belong to a special genus of Fungi described under the name “Rhizomorpha.” The mycelium lives parasitically on the Conifers and other trees, forcing its hyphæ into the bark and between the bark and wood, and thence penetrating into the wood so that the tree is very severely attacked. It may also live saprophytically, and clusters of fruit-bodies are often found on old stumps and stems, on old timber, and in the rich soil of woods. The rhizomorpha, living underground, can extend for considerable distances and infect the roots of neighbouring trees, and spreads in this way the diseases known as “Harzsticken” and “Bark-Canker,” which are very destructive to young trees.
Fig. 174.—Psalliota campestris. A Tangential section of pileus showing lamellæ (l). B Portion of gill more highly magnified; t trama; hy hymenium with basidia and basidiospores; sh, subhymenial layer. C A portion of the same more highly magnified; s′ s′′ s′′′ s′′′′ various stages in the development of basidiospores; q paraphyses.
The chief characteristics by which the numerous genera are separated are the presence or the absence of the two kinds of veils, the nature of the fruit-body, the form, branching of the lamellæ, and their position and relation with respect to the stem, the shape of the pileus, the colour of the spores, etc., etc. A knowledge of the colour may be obtained by placing the pileus with the lamellæ turned downwards on a piece of white or coloured paper, so that the spores, as they fall off, are collected on the paper, and the arrangement of the lamellæ can then be clearly seen.
Fig. 175.—Cantharellus cibarius (reduced).
Fig. 176.—Armillaria mellea. (½ nat. size): a root of a Fir; b rhizomorpha-strands; c-f fruit-bodies in four different stages of development.
Fig. 177.—The mycelium of Armillaria mellea (“Rhizomorpha”) (nat. size).
About 4,600 species belonging to this order have been described.
On account of the large number of species the order is divided into several sections:
1. Agaricinei; fruit-body fleshy; lamellæ membranous, knife-like, with sharp edge; basidia crowded together. The FOLLOWING HAVE WHITE SPORES:—Amanita (Fly Mushroom), with volva, and generally also the upper ring on the stalk; many are poisonous, such as A. muscaria (Fig. 178) which has bright red pileus with white spots, A. pantherina and A. phalloides; A. cæsarea is edible.—Lepiota procera (Parasol Fungus) is one of the largest Mushrooms; it has a scaly pileus and moveable ring (edible).—Armillaria mellea has been mentioned above (Figs. 176, 177).—Tricholoma, lamellæ indented near the stalk; T. gambosum (Pomona Fungus) belongs to the best of edible Fungi; T. personatum often forms fairy rings (see above).—Clitocybe, lamella decurrent; C. nebularis is edible.—Pleurotus, stalk eccentric; P. ostreatus (Oyster Mushroom) grows in clusters on tree-stems (edible).—Collybia and Mycena, species numerous, small.—Spores rose-red: Volvaria and Hyporhodius.—Spores Brown: Cortinarius, with cobweb-like veil; Pholiota, membranous veil and ring; P. squarrosa in clusters on tree-stems; P. mutabilis, on tree-stumps (edible).—Spores Violet-purple: Hypholoma, Psalliota; to this section the common edible Mushroom (Fig. 172–174) belongs, with annulus and chocolate-coloured lamellæ; it is cultivated for the sake of the fine flavour.—Spores Black: Coprinarius.
Fig. 178.—Fly Mushroom (Amanita muscaria).
2. Marasmiei. Fruit-body tough, almost leathery, and persistent; spores white. Marasmius oreades forms large, regular fairy-rings on pastures and commons; it is used as seasoning in food.—Panus stipticus with eccentrically-placed stalk, in clusters on tree-stumps.—Schizophyllum has the edge of the lamellæ divided longitudinally, and the split portions revolute.—Lentinus affords a transition to Dædalea among the Polyporaceæ.
3. Russulei. Fruit-body fleshy and fragile, in which two different systems of hyphæ may be distinguished; spores thorny, white, or pale-yellow. Many are poisonous.—Russula has generally fragile and thick lamellæ reaching from stalk to edge of pileus; pileus frequently red.—Lactarius has white or yellow milky juice, which often is very acid. L. deliciosus has red-yellow milky juice, and is of a pleasant flavour. L. torminosus is poisonous.
4. Hygrophorei. Lamellæ thick and waxy, widely separated; spores white. Many species of Hygrophorus have brightly-coloured pileus and grow among the grass on moors and commons.—Nyctalis is parasitic on larger Toadstools. It is remarkable for its abundant formation of chlamydospores, whilst the basidiospores are little developed.
5. Coprinei. Fruit-bodies very soft, quickly perishable; lamellæ membranous and deliquescent. The basidia are separated from each other by paraphyses. Coprinus has coal-black spores, grows on manure, and sometimes developes sclerotia.
6. Paxillei. Fruit-body fleshy; lamellæ easily detached from the pileus and reticulately-joined near the stalk. They form a connecting link between the Agaricaceæ and Boletus.
7. Cantharellei. Lamellæ reduced to dichotomously-divided folds, decurrent on the stalk. Cantharellus cibarius (Fig. 175) is yolk-yellow, and grows on the ground in woods (edible). It is allied to Craterellus.
Family 3. Phalloideæ.
The fruit-bodies before they are ripe are spherical or ovoid, and enclosed by a fleshy covering, the peridium, which is perforated at maturity and remains as a sheath (Fig. 179); the fruit-bodies are hemiangiocarpic.
Order 1. Phallaceæ (Stink-horns). The peridium has a complicated structure and is composed of three layers, the intermediate one being thick and gelatinous. The gleba (the tissue which bears the hymenium) is situated upon a peculiar receptacle which expands into a porous stalk and by its sudden distension, rupturing the peridium, elevates the gleba and hymenium above the peridium, which remains as a sheath. The gleba becomes gelatinous and dissolves away as drops. To this order belong many peculiar and often brightly coloured forms, which are natives of the Southern Hemisphere.
Phallus impudicus (Stink-horn) (Fig. 179), has a fruit-body which at first is white, heavy, and soft, and resembles a hen’s egg in shape and size. The peridium is divided into three layers (Fig. 179 e, g, f) of which the external and internal are membranous, and the middle one very thick and gelatinous; each of these has again a laminated structure. The peridium when ruptured remains as a sheath (k) at the base of the stalk. The receptacle at first is strongly compressed (h) but afterwards expands into a long stalk (l) which bears the conical gleba (m). Prior to the rupture of the peridium the gleba consists of a greenish mass (i) which, when exposed, emits a carrion-like stench serving to attract flies, by whose agency the spores are distributed. It is found commonly in hedgerows and in woods, growing on the ground. The much smaller and less common P. caninus is found on rotten tree-stumps.—In Clathrus cancellatus the receptacle expands into a bright red, reticulate structure. A native of the South of Europe. Colus, Aseroë, Mitromyces.
Order 2. Sphærobolaceæ. An intermediate layer of the peridium swells when ripe, becomes convex, and ejects the remaining spherical portion of the fruit-body which contains the spores. Sphærobolus carpobolus has small, spherical fruit-bodies which open in the form of a star.
Fig. 179.—Phallus impudicus (Stink-horn), somewhat diminished. Fruit-bodies in all stages of development (b, c, d and k-m) are seen arising from a root-like mycelium (a); d longitudinal sections through a fruit-body before the covering has ruptured.
Family 4. Gasteromycetes.
The fruit-body is angiocarpic, fleshy at first, and later generally more or less hard and continues closed after the spores are ripe. The tissue lying immediately inside the peridium is termed the gleba; it is porous, containing a larger or smaller number of chambers lined with the hymenium, which is either a continuous layer of basidia or else it fills up the entire cavity. The basidia as a rule bear four spores, sometimes eight (Geaster), or two (Hymenogaster). The tissue of the walls (trama) consists often (Lycoperdaceæ) of two kinds of hyphæ, some thin and rich in protoplasm, divided by transverse septa and bearing the basidia; others thicker and thick-walled which do not dissolve like the former on the ripening of the spores, but continue to grow and form a woolly, elastic mass, the capillitium, which may be regarded as highly developed paraphyses. The peridium may be either single or double, and presents many variations in its structure and dehiscence. The mycelium is generally a number of string-like strands, living in soils rich in humus.
Order 1. Tylostomaceæ. Capillitium present. After the rupture of the peridium the remaining part of the fruit-body is elevated on a long stalk. Tylostoma mammosum, on heaths.
Order 2. Lycoperdaceæ. The fruit-body has a double peridium; the external one at length breaks into fragments (Lycoperdon, Bovista), or it has a compound structure of several layers (Geaster) and detaches itself as a continuous envelope from the inner layer, which is membranous and opens at its apex. The interior of the fruit-body consists either solely of the fertile gleba (Bovista, Geaster), or, in addition, of a sterile tissue at the base (Lycoperdon). A capillitium is also present.
Fig. 180.—Lycoperdon gemmatum (½ nat. size).
Lycoperdon (Puff-ball) has a sterile part at the base of the fruit-body which often forms a thick stalk. The surface of the peridium is generally covered with warts or projections. When young this Fungus is edible, but when ripe it is dry, and used for stopping the flow of blood. L. giganteum, which is often found growing in meadows, attains a considerable size, its diameter reaching as much as eighteen inches. L. gemmatum (Fig. 180) is covered with pyramidal warts; in woods.—Bovista has no sterile basal part; the external peridium is smooth, and falls away in irregular patches. B. plumbea, on links near the sea.—Geaster (Earth-star) has an external peridium composed of several layers, which when the fruit-body opens, split into several stellate segments. These segments are very hygroscopic, and in dry weather bend backwards and so raise the inner peridium into the air. The inner peridium contains the spores and capillitia. G. coliformis has several apertures in the inner peridium. The other species have only one regular aperture at the apex. G. striatus has a pedicellate inner peridium, with conical, striped peristome. G. fornicatus has an external peridium split into four segments. This last and several other species produce “mycorhiza” on the roots of Conifers.
Fig. 181.—I Hymenogaster citrinus (nat. size); II longitudinal section through H. tener (× 5); III portion of a section of H. calosporus; g a chamber; h hymenium; sp. spores; t trama (× 178); IV Rhizopogon luteolus (nat. size); V Scleroderma vulgare, VI section of V; VII basidia with spores belonging to the same Fungus.
Order 3. Sclerodermataceæ. Capillitium wanting. The peridium is simple and thick, gleba with round, closed chambers, which are filled with basidia.
Scleroderma has a corky peridium. The fruit-bodies commence their development under ground. S. vulgare (Fig. 181 V-VII), has a hard, slaty-black gleba.
Order 4. Nidulariaceæ (Nest-Fungi). Small Fungi of which the fruit-body at first is spherical or cylindrical but upon maturity it becomes cupular or vase-like, and contains several lenticular “peridiola” lying like eggs in a nest. The peridiola are the chambers which contain the hymenium, covered by a thin layer of the gleba, all the remaining portion of the gleba becoming dissolved. On decaying wood.
Nidularia has spherical fruit-bodies containing a large number of lenticular peridiola, embedded in a slimy mass.—Crucibulum has fruit-bodies resembling crucibles with discoid peridiola, each with a spirally-twisted stalk.—Cyathus has a fruit-body, which when open is campanulate, with stratified peridium, and long-stalked, lense-shaped peridiola.
Order 5. Hymenogastraceæ. Fruit-bodies tubercular, globose and subterranean, resembling very closely the Truffles, from which they can only be distinguished with certainty by microscopic means. The peridium is simple, capillitium wanting, and the gleba encloses a system of labyrinthine passages covered with a continuous hymenium. The fruit-bodies persist for some time, and form a fleshy mass, the spores being only set free by the decay of the fruit-body, or when it is eaten by animals. The majority are South European. Hymenogaster, Melanogaster, Rhizopogon (Fig. 181 I-IV).
Appendix to the Basidiomycetes:
Basidiolichenes (Lichen-forming Basidiomycetes).
Several Fungi belonging to the Basidiomycetes have a symbiotic relationship with Algæ exactly similar to that enjoyed by certain Ascomycetes, and these are therefore included under the term Lichens (p. 136). They are chiefly tropical.
Order 1. Hymenolichenes. To this order belong some gymnocarpic forms: Cora, Dictyonema, Laudatea.[15]
Order 2. Gasterolichenes. To this belong some angiocarpic forms: Emericella, Trichocoma.
Appendix to the Fungi.
Fungi imperfecti (Incompletely known Fungi).
1. The Saccharomyces-forms are Fungi which are only known in their yeast-conidial form. They are conidia of higher Fungi which can multiply to an unlimited extent by budding in nutritive solutions, and in this way maintain their definite size and shape. The budding takes place only at the ends of the conidia. The wall of the conidium forms at one or at both ends a small wart-like outgrowth, which gradually becomes larger, and is finally separated from its mother-cell as an independent cell, surrounded by a closed cell-wall (Fig. 182 a, b).
Fig. 182.—Beer-yeast (Saccharomyces cerevisiæ): a-b (× 400); c-f (× 750); c a cell in the process of forming spores; d a cell with four ripe spores; e the spores liberated by the dissolution of the cell-wall; f three germinating spores; g mycelium-like cell-chains. (× 1000: after Em. Chr. Hansen.)
Under very favourable conditions multiplication occurs so rapidly that the daughter-cells themselves commence to form buds, before they have separated from their mother-cell, with the result that pearl-like chains of cells are produced. When the yeast-cells have only limited nutriment, with an abundant supply of air, at a suitable temperature, an endogenous formation of spores takes place. The protoplasm of the cells divides into 1–4 (rarely a greater number) masses (Fig. 182 c, d, e) which surround themselves with a thick cell-wall, and in this state can withstand adverse conditions and periods of dryness lasting for several months.
The sporangia are not asci since they have no definite form, and a definite number, form and size of spores is not found. The spores in the different species and kinds occupy varying periods for their development, although exposed to the same temperature, a fact of importance in determining one from another. On germination the wall of the mother-cell is destroyed, and each spore gives rise to a new cell, multiplication taking place by budding (Fig. 182 f). The majority of Yeast-Fungi are able to produce alcoholic fermentation in saccharine fluids.
The most important of these Fungi is the Beer-yeast (Saccharomyces cerevisiæ) with ovate, ellipsoidal or spherical cells (Fig. 182). It is a plant which has been cultivated from time immemorial, on account of its property of producing alcoholic fermentation in sugar-containing extracts (wort), derived from germinating barley (malt). Carbonic acid is also set free during this process. The “surface-yeast” (Fig. 182 a), which produces ordinary beer when the brewing takes place at higher temperatures, has cell-chains; “sedimentary yeast” (Fig. 182 b), used in the brewing of Bavarian beer, has spherical cells, solitary, or united in pairs. Both these and the following Yeast-Fungi include, according to Hansen, several species and kinds.