=Trogia crispa= Fr.--This species is the principal if not only one in Europe and America. It is widely distributed, and sometimes not very uncommon. It occurs on trunks, branches, etc., often on the birch. The plants are from 0.5--1 cm. broad, usually sessile. The upper surface is whitish or reddish yellow toward the attachment, sometimes tan color, and when young it is sometimes covered with whitish hairs. The gills are very narrow, vein-like, irregular, interrupted or continuous, and often more or less branched. The gills are very much crisped, hence the name, blunt at the edge and white or bluish gray. The caps are usually much crowded and overlapped in an imbricated fashion as shown in Fig. 134; a photograph of a fine specimen after being moistened. CHAPTER VII. THE ROSY-SPORED AGARICS. The spores are rosy, pink, salmon colored, flesh colored, or reddish. For analytical keys to the genera see Chapter XXIV. PLUTEUS Fr. In the genus _Pluteus_ the volva and annulus are both wanting, the gills are usually free from the stem, and the stem is easily broken out from the substance of the cap, reminding one in some cases of a ball and socket joint. The substance of the cap is thus said to be not continuous with that of the stem. The spores seen in mass are flesh colored as in other genera of this subdivision of the agarics. [Illustration: FIGURE 135.--Pluteus cervinus. Cap grayish brown, or sooty, smooth or sometimes scaly, rarely white, stem same color, but paler; gills first white, then flesh color (natural size, often larger). Copyright.] =Pluteus cervinus= Schaeff. =Edible.=--This is one of the very common species of the higher fungi, and is also very widely distributed. It varies considerably in size and appearance. It is 7--15 cm. high, the cap 5--10 cm. broad, and the stem 6--12 mm. in thickness. It occurs on the ground from underground roots or rotten wood, or grows on decaying stumps, logs, etc., from spring until late autumn. Sometimes it is found growing in sawdust. The =pileus= is fleshy, bell-shaped, then convex, and becoming expanded, the surface usually smooth, but showing radiating fibrils, grayish brown, or sometimes sooty, sometimes more or less scaly. The =gills= are not crowded, broad, free from the stem, white, then becoming flesh color with the maturity of the spores. One very characteristic feature of the plant is the presence of =cystidia= in the hymenium on the gills. These are stout, colorless, elliptical, thick-walled, and terminate in two or three blunt, short prongs. The =stem= is nearly equal, solid, the color much the same as that of the pileus, but often paler above, smooth or sometimes scaly. In some forms the plant is entirely white, except the gills. In addition to the white forms occurring in the woods, I have found them in an old abandoned cement mine growing on wood props.