FIG. 86. Germinating pseudospore of Triphragmium Ulmariæ 87. Germinating pseudospore of Phragmidium bulbosum. 88. Germinating pseudospores of Podisoma Juniperi 89. Germinating pseudospore of Tilletia caries 90. Pseudospore of Ustilago receptaculorum in germination, and secondary spores in conjugation 91. Conidia and zoospores of Cystopus candidus 92. Resting spore of Cystopus candidus with zoospores 103. Erysiphe cichoraccarum, receptacle and mycelium 106. Nectria with Tubercularia, ascus and paraphyses 151 151 152 158 161 165 167 169 171 FUNGI THEIR NATURE, USES, INFLUENCES, ETC. I. NATURE OF FUNGI. THE most casual observer of Nature recognizes in almost every instance that comes under his notice in every-day life, without the aid of logical definition, the broad distinctions between an animal, a plant, and a stone. To him, the old definition that an animal is possessed of life and locomotion, a plant of life without locomotion, and a mineral deficient in both, seems to be sufficient, until some day he travels beyond the circuit of diurnal routine, and encounters a sponge or a zoophyte, which possesses only one of his supposed attributes of animal life, but which he is assured is nevertheless a member of the animal kingdom. Such an encounter usually perplexes the neophyte at first, but rather than confess his generalizations to have been too gross, he will tenaciously contend that the sponge must be a plant, until the evidence produced is so strong that he is compelled to desert his position, and seek refuge in the declaration that one kingdom runs into the other so imperceptibly that no line of demarcation can be drawn between them. Between these two extremes of broad distinction, and no distinction, lies the ground occupied by the scientific student, who, whilst admitting that logical definition fails in assigning briefly and tersely the bounds of the three kingdoms, contends B that such limits exist so positively, that the universal scientific mind accepts the recognized limit without controversy or contradiction. In like manner, if one kingdom be made the subject of inquiry, the same difficulties will arise. A flowering plant, as represented by a rose or a lily, will be recognized as distinct from a fern, a seaweed, or a fungus. Yet there are some flowering plants which, at first sight, and without examination, simulate cryptogams, as, for example, many Balanophore, which the unscientific would at once class with fungi. It is nevertheless true that even the incipient botanist will accurately separate the phanerogams from the cryptogams, and by means of a little more, but still elementary knowledge, distribute the latter amongst ferns, mosses, fungi, lichens, and algæ, with comparatively few exceptions. It is true that between fungi and lichens there exists so close an affinity that difficulties arise, and doubts, and disputations, regarding certain small groups or a few species; but these are the exception, and not the rule. Botanists generally are agreed in recognizing the five principal groups of Cryptogamia, as natural and distinct. In proportion as we advance from comparison of members of the three kingdoms, through that of the primary groups in one kingdom, to a comparison of tribes, alliances, and orders, we shall require closer observation, and more and more education of the eye to see, and the mind to appreciate, relationships and distinctions. We have already assumed that fungi are duly and universally admitted, as plants, into the vegetable kingdom. But of this fact some have even ventured to doubt. This doubt, however, has been confined to one order of fungi, except, perhaps, amongst the most illiterate, although now the animal nature of the Myxogastres has scarcely a serious advocate left. In this order the early condition of the plant is pulpy and gelatinous, and consists of a substance more allied to sarcode than cellulose. De Bary insinuated affinities with Amaba,* whilst Tulasne * De Bary, "Des Myxomycètes," in "Ann. des Sci. Nat." 4 sér. xi. p. 153; "Bot. Zeit." xvi. p. 357. De Bary's views are controverted by M. Wigand in "Ann. des Sci. Nat." 4 sér. (Bot.) xvi. p. 255, &c. affirmed that the outer coat in some of these productions contained so much carbonate of lime that strong effervescence took place on the application of sulphuric acid. Dr. Henry Carter is well known as an old and experienced worker amongst amoeboid forms of animal life, and, when in Bombay, he devoted himself to the examination of the Myxogastres in their early stage, and the result of his examinations has been a firm conviction that there is no relationship whatever between the Myxogastres and the lower forms of animal life. De Bary has himself very much modified, if not wholly abandoned, the views once propounded by him on this subject. When mature, and the dusty spores, mixed with threads, sometimes spiral, are produced, the Myxogastres are so evidently close allies of the Lycoperdons, or Puffballs, as to leave no doubt of their affinities. It is scarcely necessary to remark that the presence of zoospores is no proof of animal nature, for not only do they occur in the white rust (Cystopus), and in such moulds as Peronospora,* but are common in algæ, the vegetable nature of which has never been disputed. There is another equally important, but more complicated subject to which we must allude in this connection. This is the probability of minute fungi being developed without the intervention of germs, from certain solutions. The observations of M. Trécul, in a paper laid before the French Academy, have thus been summarized:-1. Yeast cells may be formed in the must of beer without spores being previously sown. 2. Cells of the same form as those of yeast, but with different contents, arise spontaneously in simple solution of sugar, or to which a little tartrate of ammonia has been added, and these cells are capable of producing fermentation in certain liquids under favourable conditions. 3. The cells thus formed produce Penicillium like the cells of yeast. 4. On the other hand, the spores of Penicillium are capable of being transformed into yeast. † The interpretation of this is, that the mould Penicillium may be * De Bary. "Recherches sur le Developpement de quelques Champignons Parasites," in "Ann. des Sci. Nat." 4 sér. (Bot.) xx. p. 5. "Popular Science Review," vol. viii. p. 96. produced from a sugar solution by "spontaneous generation," and without spore or germ of any kind. The theory is, that a molecular mass which is developed in certain solutions or infusions, may, under the influence of different circumstances, produce either animalcules or fungi. In all these cases, no kind of animalcule or fungus is ever seen to originate from preexisting cells or larger bodies, but always from molecules."* The molecules are said to form small masses, which soon melt together to constitute a globular body, from which a process juts out on one side. These are the so-called Torula, † which give off buds which are soon transformed into jointed tubes of various diameters, terminating in rows of sporules, Penicillium, or capsules containing numerous globular seeds, Aspergil. lus (sic). This is but another mode of stating the same thing as above referred to by M. Trécul, that certain cells, resembling yeast cells (Torula), are developed spontaneously, and that these ultimately pass through the form of mould called Penicillium to the more complex Mucor (which the writer evidently has confounded with Aspergillus, unless he alludes to the ascigerous form of Aspergillus, long known as Eurotium). From what is now known of the polymorphism of fungi, there would be little difficulty in believing that cells resembling yeast cells would develop into Penicillium, as they do in fact in what is called the "vinegar plant," and that the capsuliferous, or higher condition of this mould may be a Mucor, in which the sporules are produced in capsules. The difficulty arises earlier, in the supposed spontaneous origination of yeast cells from molecules, which result from the peculiar conditions of light, temperature, &c., in which certain solutions are placed. It would be impossible to review all the arguments, or tabulate all the experiments, which have been employed for and against this theory. It could not be passed over in silence, since it has been one of the stirring questions of the day. The great problem how to exclude all germs * Dr. J. H. Bennett "On the Molecular Origin of Infusoria," p. 56. They have, however, no close relation with real Torule, such as T. mon lioides, &c.-COOKE's Handbook, p. 477. |