_Agaricon_, a Greek name for fungi, said to be derived from the name of a town, Agara. =Pileus= fleshy, flesh of the stem different from that of the pileus, furnished with a distinct ring. =Gills= at first enclosed by the veil, free, rounded behind, at first white or whitish, in some species this stage lasting but a short time, then pink or reddish, at length dark purplish-brown from the spores. =Spores= brown, brownish or reddish-purple. On the ground, generally in pastures, meadows or manured ground, a few species occur in woods. Analogous with Lepiota of the white-spored series. Stropharia also bears a ring and has similar colored spores, but is separated by the flesh of stem and pileus being continuous and the gills being more or less adnate. Formerly in Agaricus as sub-genus Psalliota (_psallion_, _psalion_, in poetry, a ring). When Psalliota was raised to generic rank it was given the name of the great genus Agaricus as a mark of distinction on account of its including the most widely known and useful mushroom of the world—Agaricus campester. The name Psalliota is not in modern use. Old Agaricus included many subgenera and consequently many more species. Now it contains but few. All of them are highly flavored and of marked excellence. Before the subgenera under Agaricus were promoted to full generic standing it was customary to state the name of a species thus: Agaricus (Psalliota) campester. Agaricus (Stropharia) semi-orbicularis. This was lengthy and clumsy. In the older books this form prevails. Often, however, the subgenus is omitted before the name, which compels the student to look up the subgenus to which the species belongs. The older books are therefore puzzling to modern students, who find there simply the name Agaricus to guide them. The present genus of a known species in old Agaricus can be easily found by looking in the index for its specific name. The name of the genus follows it in parentheses. All of the genus can be cooked in any desired way. ANALYSIS OF SPECIES. * Gills at first or very soon pink or rosy. ** Gills at first brownish or gray. *** Gills at first white or whitish. * _Gills at first or very soon pink or rosy._ =A. campes´ter= Linn.—_campus_, a field. (Plate XCI, fig. 4 (3 figs.) fig. 5, section, p. 332). =Pileus= at first hemispherical or convex, then expanded with decurved margin or nearly plane, smooth, silky floccose or hairy squamulose, the margin extending beyond the lamellæ, the flesh rather thick, firm, white. =Lamellæ= free, close, ventricose, _at first delicate pink or flesh color_, then blackish-brown, _subdeliquescent_. =Stem= equal or slightly thickened toward the base, _stuffed_, white or whitish, nearly or quite smooth. =Ring= at or near the middle, more or less lacerated, sometimes evanescent. =Spores= elliptical, 6–8×4–5µ.