This plant is said to differ from the common mushroom (_A. campestris_) in the more deeply hemispherical cap of the young plant, the hollow and somewhat bulbous stem, and in the scales on the under side of the annulus. In fresh plants the flesh has also a flavor of almonds. It is closely related to =A. silvaticus= Schaeff., p. 62, T. 242, Icones Fung. Bav. etc., 1770, if not identical with it. _A. silvaticus_ has light ochraceous or subrufescent scales on the cap, a strong odor, and occurs in gardens as well as in the woods. =Agaricus (Psalliota) fabaceus= Berk., was described in Hooker's London Journal of Botany, =6=: 314, 1847, from specimens collected in Ohio. The plant is white and is said to have a strong but not unpleasant odor. _Agaricus amygdalinus_ Curt., from North Carolina, and of which no description was published, was so named on account of the almond-like flavor of the plant. Dr. Farlow suggests (Proc. Bost. Soc. Nat. Hist. =26=: 356--358, 1894) that _A. fabaceus_, _amygdalinus_, and _subrufescens_ are identical. =Agaricus (Psalliota) placomyces= Pk. =Edible.=--The flat-cap mushroom, _Agaricus placomyces_ Pk., occurs in borders of woods or under trees from June to September. According to Peck it occurs in borders of hemlock woods, or under hemlock trees. At Ithaca it is not always associated with hemlock trees. The largest specimens found here were in the border of mixed woods where hemlock was a constituent. It has been found near and under white pine trees in lawns, around the Norway spruce and under the Norway spruce. The plants are from 5--15 cm. high, the cap from 5--12 cm. in diameter, and the stem 6--8 mm. in thickness. The =pileus= when young is broadly ovate, then becomes convex or fully expanded and flat in age, and is quite thin. The ground color is whitish, often with a yellowish tinge, while the surface is ornamented with numerous minute brownish scales which are scattered over a large part of the cap, but crowded or conjoined at the center into a large circular patch. This gives to the plant with its shapely form a beautiful appearance. In the young stage the entire surface of the pileus is quite evenly brown. As it expands the outer brown portion is torn asunder into numerous scales because the surface threads composing this brown layer cease to grow. These scales are farther apart toward the margin of the cap, because this portion of the cap always expands more than the center, in all mushrooms. The =gills= are at first white, or very soon pink in color, and in age are blackish brown. Spores 5--8 × 3--4 µ.