cated, and these are no longer regarded so much as species of Hendersonia or Diplodia as the pycnidia of Sphæria. Other and more minute perithecia, containing minute, slender stylospores in great numbers, formerly classed with Aposphæria, Phoma, &c., but are now recognized as spermogonia containing the spermatia of Sphæriæ. How these influence each other, when and under what circumstances the spermatia are instrumental in impregnation of the sporidia, is still matter of mystery. It is clear, however, that in all these conidia, macrospores, microspores, and some spermatia, or by whatever names they may be called, there exists a power of germination. Tulasne has indicated in some instances five or six forms of fruit as belonging to one fungus, of which the highest and most perfect condition is a species of Sphæria. FIG. 36.-Uncinula adunca. 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.* 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 * Tulasne, "Selecta Fungorum Carpologia," vol. i. Léveillé, “Organisation, &c., sur l'Erysiphé," in "Ann. des Sci. Nat." (1851), vol. xv. p. 109. is very analogous to such a genus of Erysiphei as Microsphæria. In Chatomium, 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.* * 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 Analytica 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." Corda, J., "Prachtflora." Prague, 1840. De Bary, "Über der Brandpilze." 1853. 1874. Brefeld, O., "Botan. Untersuch. ü Schimmelpilze." Von Tieghem and Le Monnier, in "Annales des Sciences Naturelles" (1873), p. 335. Cornu, M., "Sur les Saprolegniées," in "Ann. des Sci. Nat." 5me sér. xv. p. 5. Janczenski, "Sur l'Ascobolus furfuraceus," in "Ann. des Sci. Nat." 5me sér. xv. p. 200. De Bary and Woronin, "Beiträge zur Morphologie und Physiologie der Pilze." 1870. Bonorden, H. F., "Abhandlungen ans 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,"* and adopted in Lindley's "Vegetable Kingdom." Another arrangement was proposed by Professor de Bary, 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 * Rev. M. J. Berkeley, "Introduction to Cryptogamic Botany" (1857), London, pp. 235 to 372. De Bary, in "Streinz Nomenclator Fungorum," p. 722. 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,* so that the fertile threads are in reality not compacted into a true hymenium. With this introduction we FIG. 37.-Agaricus nudus. 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 Tulasne, L. and C. R., "Observations sur l'Organisation des Trémellinées," "Ann. des Sci. Nat." 1853, xix. p. 193. * |