Chapter 7

PERISPORIACEI.--Except in the perithecia rupturing irregularly, and not dehiscing by a pore, some of the genera in this group differ little in structure from the _Sphæriacei_. On the other hand, the _Erysiphei_ present important and very interesting features. They occur chiefly on the green parts of growing plants. At first there is a more or less profuse white mycelium.[AC] This gives rise to chains of conidia (_Oidium_), and afterwards small sphæroid projections appear at certain points on the mycelium. These enlarge, take an orange colour, ultimately passing into brown, and then nearly black. Externally these perithecia are usually furnished with long, spreading, intertwined, or branching appendages, sometimes beautifully branched or hooked at their tips. In the interior of the receptacles, pear-shaped or ovate asci are formed in clusters, attached together at the base, and containing two or more hyaline sporidia. Other forms of fruit have also been observed on the same mycelium. In an exotic genus, _Meliola_, the fulcra, or appendages, as well as the mycelium, are black, otherwise it is very analogous to such a genus of _Erysiphei_ as _Microsphæria_. In _Chætomium_, the perithecia bristle with rigid, dark-coloured hairs, and the sporidia are coloured. Our limits, however, will not permit of further elucidation of the complex and varied structure to be found amongst fungi.[AD]

[A] A curious case occurred some years since at Bury St. Edmunds, which may be mentioned here in connection with the development of these nodules. Two children had died under suspicious circumstances, and an examination of the body of the latter after exhumation was made, a report having arisen that the child died after eating mushrooms. As certain white nodules appeared on the inner surface of the intestines, it was at once hastily concluded that the spores of the mushroom had germinated, and that the nodules were infant mushrooms. This appeared to one of us so strange, that application was made for specimens, which were kindly forwarded, and a cursory glance was enough to convince us that they were not fungoid. An examination under the microscope further confirmed the diagnosis, and the application of nitric acid showed that the nodules were merely due to chalk mixture, which had been given to the child for the diarrhetic symptoms under which he succumbed.

[B] Ehrenberg compared the whole structure of an Agaric with that of a mould, the mycelium corresponding with the hyphasma, the stem and pileus with the flocci, and the hymenium with the fructifying branchlets. The comparison is no less ingenious than true, and gives a lively idea of the connection of the more noble with the more humble fungi.--_Ehrb. de Mycetogenesi._

[C] In _Paxillus involutus_ the hymenium may be readily torn off and unfolded.

[D] This was well delineated in "Flora Danica," plate 834, as observed in _Coprinus comatus_ as long ago as 1780.

[E] A. de Bary, "Morphologie und Physiologie der Pilze," in "Hofmeister's Handbuch," vol. ii. cap. 5, 1866, translated in "Grevillea," vol. i. p. 181.

[F] "Die Pollinarien und Spermatien von _Agaricus_," in "Botanische Zeitung," Feb. 29 and March 7, 1856.

[G] "Essai d'une Flore mycologique de la Région de Montpellier." Paris, 1863.

[H] Hoffmann, "Botanische Zeitung," 1856, p. 139.

[I] Corda, "Icones Fungorum hucusque cognitorum," iii. p. 41. Prague, 1839.

[J] Cooke, M. C., "Anatomy of a Mushroom," in "Popular Science Review," vol. viii. p. 380.

[K] An attempt was made to show that, in _Agaricus melleus_, distinct asci were found, in a certain stage, on the gills or lamellæ. We have in vain examined the gills in various conditions, and could never detect anything of the kind. It is probable that the asci belonged to some species of _Hypomyces_, a genus of parasitic Sphæriaceous fungi.

[L] It is not intended that the spores are always quaternate in _Agaricini_, though that number is constant in the more typical species. They sometimes exceed four, and are sometimes reduced to one.

[M] The species long known as _Hydnum gelatinosum_ was examined by Mr. F. Currey in 1860 (_Journ. Linn. Soc._), and he came to the conclusion that it was not a good _Hydnum_. Since then it has been made the type of a new genus (Hydnogloea B. and Br. or, as called by Fries, in the new edition of "Epicrisis," _Tremellodon_, Pers. Myc. Eur.), and transferred to the _Tremellini_. Currey says, upon examining the fructification, he was surprised to find that, although in its external characters it was a perfect _Hydnum_, it bore the fruit of a _Tremella_. If one of the teeth be examined with the microscope, it will be seen to consist of threads bearing four-lobed sporophores, and spores exactly similar to _Tremella_. It will thus be seen, he adds, that the plant is exactly intermediate between _Hydnei_ and _Tremellini_, forming, as it were, a stepping-stone from one to the other.

[N] Tulasne, L. R. and C., "Observations on the Organization of the Tremellini," in "Ann. des Sci. Nat." 3^me sér. xix. (1853), pp. 193, &c.

[O] M. Léveillé, in "Ann. des Sci. Nat." 2^me sér. viii. p. 328; 3^me sér. ix. p. 127; also Bonorden, "Handbuch der Mycologie," p. 151.

[P] Tulasne, in "Ann. des Sci. Nat." (loc. cit.) xix. pl. x. fig. 29. Tulasne, "New Notes upon Tremellinous Fungi," in "Journ. Linn. Soc." vol. xiii. (1871), p. 31.

[Q] Berkeley, M. J., "On the Fructification of Lycoperdon, Phallus, &c.," in "Ann. Nat. Hist." 1840, vol. iv. p. 158, pl. 5. Berkeley, M. J., "Introduction Crypt. Bot." p. 346.

[R] Tulasne, L. R. and C., "Fungi Hypogæi." Paris. Berkeley and Broome, "British Hypogæous Fungi," in "Ann. Nat. Hist." 1846, xviii. p. 74. Corda, "Icones Fungorum," vol. vi. pl. vii. viii.

[S] Tulasne, "Sur le Genre _Secotium_," in "Ann. des Sci. Nat." (1845), 3^me sér. vol. iv. p. 169, plate 9.

[T] Tulasne, L. R. and C., "De la Fructification des _Scleroderma_ comparée a celle des _Lycoperdon_ et des _Borista_," in "Ann. des Sci. Nat." 1842, xvii. p. 5. Tulasne, L. R. and C., "Sur les Genres Polysaccum et Geaster," in "Ann. des Sci. Nat." 1842, xviii. p. 129, pl. 5 and 6.

[U] Berkeley, "On the Fructification of Lycoperdon, &c.," in "Annals of Natural History" (1840), iv. p. 155.

[V] Wigand, "Morphologie des Genres Trichia et Arcyria," in "Ann. des Sci. Nat." 4^me sér. xvi. p. 223.

[W] Currey, "On Spiral Threads of Trichia," in "Quart. Journ. Micr. Science" (1855), iii. p. 17.

[X] In some of the genera, as, for instance, in _Badhamia_, _Enerthenema_, and _Reticularia_, the spores are produced within delicate cells or cysts, which are afterwards absorbed.

[Y] Tulasne, "Essai d'une Monographie des Nidulariées," in "Ann. des Sci. Nat." (1844), i. 41 and 64.

[Z] Berkeley, M. J., "Introduction, Crypt. Bot." p. 330.

[a] Berkeley, M. J., "Introduction, Crypt. Bot." p. 329.

[b] In the _Cæomacei_ and _Pucciniæi_ the term "pseudospore" would be much more accurate.

[c] Léveillé, "Sur la Disposition Méthodique des Urédinées," in "Ann. des Sci. Nat." (1847), vol. viii. p. 369.

[d] De Bary, "Champignons Parasites," in "Ann. des Sci. Nat." 4^me sér. vol. xx.

[e] Tulasne, "Mémoire sur les Urédinées, &c.," in "Ann. des Sci. Nat." (1854), vol. ii. p. 78.

[f] De Bary, "Ueber die Brandpilze," Berlin, 1853.

[g] Currey, in "Quart. Journ. Micr. Sci." (1857), vol. v. p. 119, pl. 8, fig 13.

[h] Cooke, "On Podisoma," in "Journal of Quekett Microscopical Club," vol. ii. p. 255.

[i] Tulasne, "Mémoire sur les Ustilaginées," in "Ann. des Sci. Nat." (1847), vii. pp. 12 and 73.

[j] Corda, "Icones Fungorum," vol. iii. fig. 45.

[k] Cooke, "On Podisoma," in "Quekett Journal," vol. ii. p. 255.

[l] It may be a question whether _Graphiola_ is not more nearly allied to _Trichocoma_ (Jungh Fl. Crypt. Javæ, p. 10, f. 7) than to the genera with which it is usually associated.--M. J. B.

[m] Cooke, "On Microscopic Moulds," in "Quekett Journal," vol. ii. plate 7.

[n] _See_ "Dendryphium Fumosum," in "Quekett Journal," vol. ii. plate 8; or, "Corda Prachtflora," plate 22.

[o] De Bary, "Champignons Parasites," in "Ann. des Sci. Nat." 4^me sér. vol. xx.

[p] Berkeley, "On the Potato Murrain," in "Journ. of Hort. Soc. of London," vol. i. (1846), p. 9.

[q] De Bary, "On Mildew and Fermentation," p. 25, reprinted from "German Quarterly Magazine," 1872; De Bary, "Morphologie und Physiologie der Pilze," (1866), 201.

[r] Cooke, "Handbook of British Fungi," vol. ii. p. 552.

[s] De Bary, "On Mildew and Fermentation," in "Quarterly German Magazine," for 1872.

[t] We are quite aware that Von Tieghem and Le Monnier, in "Ann. des Sci. Nat." 1873, p. 335, dispute that this belongs to _Mucor mucedo_, and assert that _Chætocladium Jonesii_ is itself a true _Mucor_, with monosporous sporangia.

[u] Vittadini, "Monographia Tuberacearum," 1831.

[v] Tulasne, "Fungi Hypogæi," 1851.

[w] Corda, "Icones Fungorum," vol. vi.

[x] Berkeley and Broome, in "Ann. of Nat. Hist." 1st ser. vol. xviii. (1846), p. 73; Cooke, in "Seem. Journ. Bot."

[y] Boudier (E.), "Mémoire sur les Ascobolés," in "Ann. des Sci. Nat." 5^me sér. vol. x. (1869).

[z] Only in some of the Discomycetes are the asci exserted.

[AA] Duby, "Mémoire sur la Tribu des Hysterinées," 1861.

[AB] Tulasne, "Selecta Fungorum Carpologia," vol. iii.

[AC] Tulasne, "Selecta Fungorum Carpologia," vol. i. Léveillé, "Organisation, &c., sur l'Érysiphé," in "Ann. des Sci. Nat." (1851), vol. xv. p. 109.

[AD] Other works besides those already cited, which may be consulted with advantage on structure, are--

Tulasne, L. R. and C., various articles in "Annales des Sciences Naturelles," série iii. and iv.

Hoffmann, "Icones Analyticæ Fungorum."

De Bary, "Der Ascomyceten." Leipzic, 1863.

Berkeley, M. J., "Introduction to Cryptogamic Botany."

Seynes, J. de, "Recherches, &c., des Fistulines." Paris, 1874.

Winter, G., "Die Deutschen Sordarien." 1874.

Corda, J., "Prachtflora." Prague, 1840.

De Bary, "Über der Brandpilze." 1853.

Brefeld, O., "Botan. Untersuch. ü Schimmelpilze."

Fresenius, G., "Beiträge zur Mykologie." 1850.

Von Tieghem and Le Monnier, in "Annales des Sciences Naturelles" (1873), p. 335.

Cornu, M., "Sur les Saprolegniées," in "Ann. des Sci. Nat." 5^me sér. xv. p. 5.

Janczenski, "Sur l'Ascobolus furfuraceus," in "Ann. des Sci. Nat." 5^me sér. xv. p. 200.

De Bary and Woronin, "Beiträge zur Morphologie und Physiologie der Pilze." 1870.

Bonorden, H. F., "Abhandlungen aus dem Gebiete der Mykologie." 1864.

Coemans, E., "Spicilége Mycologique." 1862, etc.

III

CLASSIFICATION

A work of this kind could not be considered complete without some account of the systematic arrangement or classification which these plants receive at the hands of botanists. It would hardly avail to enter too minutely into details, yet sufficient should be attempted to enable the reader to comprehend the value and relations of the different groups into which fungi are divided. The arrangement generally adopted is based upon the "Systema Mycologicum" of Fries, as modified to meet the requirements of more recent microscopical researches by Berkeley in his "Introduction,"[A] and adopted in Lindley's "Vegetable Kingdom." Another arrangement was proposed by Professor de Bary,[B] but it has never met with general acceptance.

In the arrangement to which we have alluded, all fungi are divided into two primary sections, having reference to the mode in which the fructification is produced. In one section, the spores (which occupy nearly the same position, and perform similar functions, to the seeds of higher plants) are naked; that is, they are produced on spicules, and are not enclosed in cysts or capsules. This section is called SPORIFERA, or spore-bearing, because, by general consent, the term _spore_ is limited in fungi to such germ-cells as are not produced in cysts. The second section is termed SPORIDIIFERA, or sporidia-bearing, because in like manner the term _sporidia_ is limited to such germ-cells as are produced in cells or cysts. These cysts are respectively known as _sporangia_, and _asci_ or _thecæ_. The true meaning and value of these divisions will be better comprehended when we have detailed the characters of the families composing these two divisions.

First, then, the section SPORIFERA contains four families, in two of which a hymenium is present, and in two there is no proper hymenium. The term _hymenium_ is employed to represent a more or less expanded surface, on which the fructification is produced, and is, in fact, the fruit-bearing surface. When no such surface is present, the fruit is borne on threads, proceeding direct from the root-like filaments of the mycelium, or an intermediate kind of cushion or stroma. The two families in which an hymenium is present are called _Hymenomycetes_ and _Gasteromycetes_. In the former, the hymenium is exposed; in the latter, it is at first enclosed. We must examine each of these separately.

The common mushroom may be accepted, by way of illustration, as a type of the family _Hymenomycetes_, in which the hymenium is exposed, and is, in fact, the most noticeable feature in the family from which its name is derived. The pileus or cap bears on its under surface radiating plates or gills, consisting of the hymenium, over which are thickly scattered the basidia, each surmounted by four spicules, and on each spicule a spore. When mature, these spores fall freely upon the ground beneath, imparting to it the general colour of the spores. But it must be observed that the hymenium takes the form of gill-plates in only one order of _Hymenomycetes_, namely, the _Agaricini_; and here, as in _Cantharellus_, the hymenium is sometimes spread over prominent veins rather than gills. Still further divergence is manifest in the _Polyporei_, in which order the hymenium lines the inner surface of pores or tubes, which are normally on the under side of the pileus. Both these orders include an immense number of species, the former more or less fleshy, the latter more or less tough and leathery. There are still other forms and orders in this family, as the _Hydnei_, in which the hymenium clothes the surface of prickles or spines, and the _Auricularini_, in which the hymenium is entirely or almost even. In the two remaining orders, there is a still further divergence from the mushroom form. In the one called _Clavariei_, the entire fungus is either simply cylindrical or club-shaped, or it is very much branched and ramified. Whatever form the fungus assumes, the hymenium covers the whole exposed surface. In the _Tremellini_, a peculiar structure prevails, which at first seems to agree but little with the preceding. The whole plant is gelatinous when fresh, lobed and convolute, often brain-like, and varying in size, according to species, from that of a pin's head to that of a man's head. Threads and sporophores are imbedded in the gelatinous substance,[C] so that the fertile threads are in reality not compacted into a true hymenium. With this introduction we may state that the technical characters of the family are thus expressed:--

_Hymenium free, mostly naked, or, if enclosed at first, soon exposed; spores naked, mostly quaternate, on distinct spicules_ = HYMENOMYCETES.

In this family some mycologists believe that fungi attain the highest form of development of which they are capable, whilst others contend that the fructification of the _Ascomycetes_ is more perfect, and that some of the noblest species, such as the pileate forms, are entitled to the first rank. The morel is a familiar example. Whatever may be said on this point, it is incontrovertible that the noblest and most attractive, as well as the largest, forms are classed under the _Hymenomycetes_.

In _Gasteromycetes_, the second family, a true hymenium is also present, but instead of being exposed it is for a long time enclosed in an outer peridium or sac, until the spores are fully matured, or the fungus is beginning to decay. The common puff-ball (_Lycoperdon_) is well known, and will illustrate the principal feature of the family. Externally there is a tough coat or peridium, which is at first pale, but ultimately becomes brown. Internally is at first a cream-coloured, then greenish, cellular mass, consisting of the sinuated hymenium and young spores, which at length, and when the spores are fully matured become brownish and dusty, the hymenium being broken up into threads, and the spores become free. In earlier stages, and before the hymenium is ruptured, the spores have been found to harmonize with those of _Hymenomycetes_ in their mode of production, since basidia are present surmounted each by four spicules, and each spicule normally surmounted by a spore.[D] Here is, therefore, a cellular hymenium bearing quaternary spores, but, instead of being exposed, this hymenium is wholly enclosed within an external sac or peridium, which is not ruptured until the spores are fully matured, and the hymenium is resolved into threads, together forming a pulverulent mass. It must, however, be borne in mind, that in only some of the orders composing this family is the hymenium thus evanescent, in others being more or less permanent, and this has led naturally enough to the recognition of two sub-families, in one of which the hymenium is more or less permanent, thus following the Hymenomycetous type; and in the other, the hymenium is evanescent, and the dusty mass of spores tends more towards the _Coniomycetes_, this being characterized as the coniospermous (or dusty-spored) sub-family.

The first sub-family includes, first of all, the _Hypogæi_, or subterranean species. And here again it becomes necessary to remind the reader that all subterranean fungi are not included in this order, inasmuch as some, of which the truffle is an example, are sporidiiferous, developing their sporidia in asci. To these allusion must hereafter be made. In the _Hypogæi_, the hymenium is permanent and convoluted, leaving numerous minute irregular cavities, in which the spores are produced on sporophores. When specimens are very old and decaying, the interior may become pulverulent or deliquescent. The structure of subterranean fungi attracted the attention of Messrs. Tulasne, and led to the production of a splendid monograph on the subject.[E] Another order belonging to this sub-family is the _Phalloidei_, in which the volva or peridium is ruptured whilst the plant is still immature, and the hymenium when mature becomes deliquescent. Not only are some members of this order most singular in appearance, but they possess an odour so foetid as to be unapproached in this property by any other vegetable production.[F] In this order, the inner stratum of the investing volva is gelatinous. When still young, and previous to the rupture of the volva, the hymenium presents sinuous cavities in which the spores are produced on spicules, after the manner of _Hymenomycetes_.[G] _Nidulariacei_ is a somewhat aberrant order, presenting a peculiar structure. The peridium consists of two or three coats, and bursts at the apex, either irregularly or in a stellate manner, or by the separation of a little lid. Within the cavity are contained one or more secondary receptacles, which are either free or attached by elastic threads to the common receptacle. Ultimately the secondary receptacles are hollow, and spores are produced in the interior, borne on spicules.[H] The appearance in some genera as of a little bird's-nest containing eggs has furnished the name to the order.

The second sub-family contains the coniospermous puff-balls, and includes two orders, in which the most readily distinguishable feature is the cellular condition of the entire plant, in its earlier stages, in the _Trichogastres_, and the gelatinous condition of the early state of the _Myxogastres_. Both are ultimately resolved internally into a dusty mass of threads and spores. In the former, the peridium is either single or double, occasionally borne on a stem, but usually sessile. In _Geaster_, the "starry puff-balls," the outer peridium divides into several lobes, which fall back in a stellate manner, and expose the inner peridium, like a ball in the centre. In _Polysaccum_, the interior is divided into numerous cells, filled with secondary peridia. The mode of spore-production has already been alluded to in our remarks on _Lycoperdon_. All the species are large, as compared with those of the following sub-family, and one species of _Lycoperdon_ attains an enormous size. One specimen recorded in the "Gardener's Chronicle" was three feet four inches in circumference, and weighed nearly ten pounds. In the _Myxogastres_, the early stage has been the subject of much controversy. The gelatinous condition presents phenomena so unlike anything previously recorded in plants, that one learned professor[I] did not hesitate to propose their exclusion from the vegetable, and recognition in the animal, kingdom as associates of the Gregarines. When mature, the spores and threads so much resemble those of the _Trichogastres_, and the little plants themselves are so veritably miniature puff-balls, that the theory of their animal nature did not meet with a ready acceptance, and is now virtually abandoned. The characters of the family we have thus briefly reviewed are tersely stated, as--

_Hymenium more or less permanently concealed, consisting in most cases of closely-packed cells, of which the fertile ones bear naked spores on distinct spicules, exposed only by the rupture or decay of the investing coat or peridium_ = GASTEROMYCETES.