Fungi: Their Nature and Uses

by M. C. Cooke

Fig. 46.—Spores of (a) Lactarius blennius; (b) Lactarius fuliginosus; (c) Lactarius quietus. (Smith.)

There are considerable differences in size and form amongst the spores of the Agaricini, although at first globose; when mature they are globose, oval, oblong, elliptic, fusiform, and either smooth or tuberculated, often maintaining in the different genera or subgenera one particular characteristic, or typical form. It is unnecessary here to particularize all the modifications which the form and colour of the spores undergo in different species, as this has already been alluded to. The spores in the Polyporei, Hydnei, &c., are less variable, of a similar character, as in all the Hymenomycetes, except perhaps the Tremellini.

Fig. 46a.—(a) Spore of Gomphidius viscidus; (b) spore of Coprinus micaceus.

Fig. 47.—Spores of (a) Polyporus cæsius; (b) Boletus parasiticus; (c) Hydnum.

When an Agaric is mature, if the stem is cut off close to the gills, and the pileus inverted, with the gills downwards on a sheet of black paper (one of the pale-spored species is best for this purpose), and left for a few hours, or all night, in that position, the paper will be found imprinted in the morning with a likeness of the under side of the pileus with its radiating gills, the spores having been thrown down upon the paper in such profusion, from the hymenium, and in greater numbers from the opposed surfaces of the gills. This little experiment will be instructive in two or three points. It will illustrate the facility with which the spores are disseminated, the immense number in which they are produced, and the adaptability of the gill structure to the economy of space, and the development of the largest number of basidiospores from a given surface. The tubes or pores in Polyporei, the spines in Hydnei, are modifications of the same principles, producing a like result.

In the Gasteromycetes the spores are produced in many cases, probably in most, if not all, at the tips of sporophores; but the hymenium, instead of being exposed, as in the Hymenomycetes, is enclosed within an outer peridium or sac, which is sometimes double. The majority of these spores are globose in form, some of them extremely minute, variously coloured, often dark, nearly black, and either externally smooth or echinulate. In some genera, as Enerthenema, Badhamia, &c., a definite number of spores are at first enclosed in delicate cysts, but these are exceptions to the general rule: this also is the case in at least one species of Hymenogaster. As the spores approach maturity, it may be observed in such genera as Stemonitis, Arcyria, Diachea, Dictydium, Cribraria, Trichia, &c., that they are accompanied by a sort of reticulated skeleton of threads, which remain permanent, and served in earlier stages, doubtless, as supports for the spores; being, in fact, the skeleton of the hymenium. It has been suggested that the spiral character of the threads in Trichia calls to mind the elaters in the Hepaticæ, and like them may, by elasticity, aid in the dispersion of the spores. There is nothing known, however, which will warrant this view. When the spores are mature, the peridium ruptures either by an external orifice, as in Geaster, Lycoperdon, &c., or by an irregular opening, and the light, minute, delicate, spores are disseminated by the slightest breath of air. Specimens of Geaster and Bovista are easily separated from the spot on which they grew; when rolling from place to place, the spores are deposited over a large surface. In the Phalloidei the spores are involved in a slimy mucus which would prevent their diffusion in such a manner. This gelatinous substance has nevertheless a peculiar attraction for insects, and it is not altogether romantic to believe that in sucking up the fetid slime, they also imbibe the spores and transfer them from place to place, so that even amongst fungi insects aid in the dissemination of species. Whether or not the Myxogastres should be included here is matter of opinion, since the mode in which the spores are developed is but little known; analogy with the Trichogastres in other points alone leading to the conclusion that they may produce basidiospores. The slender, elastic stems which support the peridia in many species are undoubted aids to the dissemination of the spores.[B]

Fig. 48.—Diachea elegans.