Suppose that it belongs to the first of the two great sections into which fungi are divided under the classification of Fries, who modified that of Persoon. The first has the spores—which represent the seeds in plants—naked, and it is called sporifera or spore-bearing. The second, which has the spores enclosed in cells or cysts, is called sporidifera or sporidia-bearing. If the cap of a gill-bearing toadstool be laid, gills downward, on a watch crystal or piece of white paper for a few hours, or, in some instances, a few minutes, a complete representation of the spaces between the gills will be found deposited as an impalpable powder. These are the spores. The first section is divided into four cohorts. Two of these have hymeniums or spore-bearing surfaces more or less expanded. These are Hymenomycetes and Gastromycetes. In Hymenomycetes the hymenium is always exposed in matured plants, as with the common mushroom. When young, some plants are covered with a membrane. In Gastromycetes the hymenium is always concealed within a covering which bursts at maturity, as with the Lycoperdons or puff-balls. Cohort Coniomycetes includes rusts, smuts, etc., formed for the most part on living plants. There is no hymenium present. The spores are produced on the ends of inconspicuous threads, free or enclosed in a bottle-like receptacle called a perithecium. Cohort Hypomycetes is composed of those species of fungi commonly called molds. The spores are produced, naked, from the ends of inconspicuous threads. In the Agaricaceæ—the first family in Hymenomycetes—the young plant is completely enveloped. (Plate III, fig. B, p. 2.) Its head is as yet undefined and its body may be classed as dumpy, but shut in and protected are a great quantity of knife-like plaits (Plate III, fig. C., p. 2), on the outer surface of which, when the plant matures, will be borne its spores. It therefore belongs to the Hymenomycetes, and to the Family Agaricaceæ—gill-bearing. If the ground becomes moist or there comes a heavy dew or a rain, the young plant, closely compacted and very solid, which has been under the surface for many days waiting its chance to get forth to light and air, rapidly swells, breaks through the moistened earth, goes rapidly to cell-making, ruptures its outside covering, the head expands and in so doing spreads out its gills or hymenium. (Plate III, figs. C, D, E, p. 2.) The membrane which covered the gills either vanishes, or gathers round the stem in the form of a ring or circular apron, or it may partially adhere to the edges of the top, cap or pileus and hang as a fringe from it; the stem elongates; the whole plant assumes the colors of its species and in a few hours or days at most it stands forth, a marvel of beauty, structure and workmanship.