Cooke divides the Marasmii into three tribes, and these again into several subdivisions. In the division Scortei of this genus are classed three species which are described in the works of most of the Continental writers; the Marasmius oreades, which has recognized value as an esculent, Marasmius urens and Marasmius peronatus, which have the reputation of being acrid and unwholesome. [Illustration: Plate III. MARASMIUS OREADES FR. (EDIBLE) The Fairy Ring Mushroom. Report of Microscopist, U. S. Department of Agriculture 1893 L. K. after Gillet. AVIL. CO. LITH. PHILA.] PLATE III. =Marasmius oreades= Fries. "_Fairy Ring Mushroom_." EDIBLE. Cap fleshy, convex at first, then nearly plane, pale yellowish red, or tawny red when young, fading to yellow or buff as the plant matures, slightly umbonate, flesh white; gills broad, wide apart, rounded or deeply notched at the inner extremity, slightly attached to or at length free from the stem, unequal in length, whitish or creamy yellow in color; stem slender, solid and tough, whitish, generally one to two inches in length and one-fourth of an inch in thickness, showing a whitish down, easily removed, not strigose or villose, as in the Marasmius urens. Spores white. This species is usually found in open grassy places, sometimes in rings, or in parts of rings, often in clusters, and writers generally agree as to its agreeable taste and odor. When properly cooked its toughness disappears. Prof. Peck describes two mushrooms which are somewhat similar in appearance to the "_Fairy Ring_," and which might be taken for it by careless observers, viz., the Naucoria semi-orbicularis, sometimes growing in company with it, and the _Collybia dryophila_, a wood variety which is sometimes found in open places. The first of these may be distinguished from the _oreades_, by the rusty brown color of the gills, its smooth stem and rusty colored spores. In the second the gills are much narrower and the stem is very smooth and hollow. The _Marasmius urens_ as described by European authors has a pale buff cap, not umbonate but flat, and at length depressed in the centre, from one to two inches across. The gills are unequal, free, very crowded; cream color, becoming brownish. The stem is solid and fibrous, densely covered with white down at the base. It is very acrid to the taste. In habit of growth it is subcaespitose; sometimes found growing in company with the M. oreades. Prof. Peck says of _M. urens_ that he has not yet seen an American specimen which he could refer to that species with satisfaction. Our experience, so far, is the same as that of Prof. Peck. _Marasmius peronatus_ has a reddish buff cap, with crowded thin gills, creamy, turning to reddish brown; the stem solid and fibrous, with yellowish filaments at the base. It is acrid in taste and is usually found among fallen leaves in woods. EXPLANATION OF PLATE III.