The cryptogamic or flowerless plants, _i. e._, those having neither stamens nor pistils, and which are propagated by spores, are divided, according to Dr. Hooper, into the following four classes:--Pteridophyta or vascular acrogens, represented by the ferns, club-mosses, etc.; Bryophyta or cellular acrogens, represented by the musci, scale-mosses, etc.; Algae, represented by the "Red Seaweeds," Diatomacae, etc.; Fungi or Amphigens, which include the molds, mildews, mushrooms, etc. The lichens, according to the "Schwendener Hypotheses," consist of ascigerous fungi parasitic on algae. FUNGI. Botanists unite in describing the plants of this class as being destitute of chlorophyll and of starch. These plants assume an infinite variety of forms, and are propagated by spores which are individually so minute as to be scarcely perceptible to the naked eye. They are entirely cellular, and belong to the class Amphigens, which for the most part have no determinate axe, and develop in every direction, in contradistinction to the Acrogens, which develop from the summit, possessing an axe, leaves, vessels, etc. Fungi are divided by systematists into two great classes: 1. Sporifera, in which the spores are free, naked, or soon exposed. 2. Sporidifera, in which the spores are not exposed, but instead are enclosed in minute cells or sacs, called asci. These classes are again subdivided, according to the disposition of the spores and of the spore bearing surface, called the hymenium, into various families. The sporiferous fungi are arranged into four families, viz: 1. _Hymenomycetes_, in which the hymenium is free, mostly naked, or soon exposed. _Example, "Common Meadow Mushroom."_ 2. _Gasteromycetes_, in which the hymenium is enclosed in a second case or wrapper, called a peridium, which ruptures when mature, thus releasing the spores. _Example, Common Puff Ball._ 3. _Coniomycetes_, in which the spores are naked, mostly terminal on inconspicuous threads, free or enclosed in a perithecium. Dust-like fungi. _Example, Rust of Wheat._ 4. _Hyphomycetes_, in which the spores are naked on conspicuous threads, rarely compacted, Thread-like fungi. _Example, Blue Mold._ Of these four subdivisions of the Sporifera, only the Hymenomycetes and the Gasteromycetes contain plants of the mushroom family, and these two together constitute the class known as the Basidiomycetes. The chief distinction of the Basidiomycetes is that the naked spores are borne on the summits of certain supporting bodies, termed basidia. These basides are swollen, club-shaped cells, surmounted by four minute tubes or spore-bearers, called sterigmata, each of which carries a spore. See Figs. 3 and 4, Plate A. These basides together with a series of elongated cells, termed paraphyses, packed closely together side by side, and intermixed with other sterile cells, called cystidia, constitute the spore-bearing surface or hymenium of the plant.