=Mycena succosa= Pk., another species of _Mycena_ with a juice, occurs on very rotten wood in the woods. It is a small plant, dull white at first, but soon spotted with black, and turning black in handling or where bruised, and when dried. Wounds exude a "serum-like juice," and the wounds soon become black. It was described by Peck under _Collybia_ in the 25th Report, p. 74. OMPHALIA Fr. The genus _Omphalia_ is closely related to _Mycena_ and _Collybia_. It differs from these mainly in the decurrent gills. In the small species of _Mycena_ where the gills are slightly decurrent, the pileus is not umbilicate as it is in corresponding species of _Omphalia_. In some of the species of _Omphalia_ the pileus is not umbilicate, but here the gills are plainly decurrent. The stem is cartilaginous. [Illustration: PLATE 33, FIGURE 103.--Omphalia campanella. Watkin's Glen, N. Y., August, 1898. Caps dull reddish-yellow. Gills yellow. Stem brownish, hairy at base. (Natural size.) Copyright.] =Omphalia campanella= Batsch.--One of the most common and widely distributed species of the genus is the little bell-omphalia, _Omphalia campanella_. It occurs throughout the summer and autumn on dead or rotten logs, stumps, branches, etc., in woods. It is often clustered, large numbers covering a considerable surface of the decaying log. It is 1--3 cm. high, the cap 8--20 mm. broad, and the stem very slender. The =pileus= is convex, umbilicate, faintly striate, dull reddish yellow, in damp weather with a watery appearance. The =gills= are narrow, yellow, connected by veins, strongly curved because of the form of the pileus, and then being decurrent on the stem. The =stem= is slender, often ascending, brownish hairy toward the base, and paler above. [Illustration: FIGURE 104.--Omphalia epichysium. Entire plant smoky or dull gray in color (natural size). Copyright.] =Omphalia epichysium= Pers.--This plant occurs during the autumn in woods, growing usually on much decayed wood, or sometimes apparently on the ground. The smoky, or dull gray color of the entire plant, the depressed or funnel-shaped pileus, and short, slender stem serve to distinguish it. The cap is 2--4 cm. broad, the plant is 3--5 cm. high, and the stem 2--4 mm. in thickness. The =pileus= is convex, becoming expanded, umbilicate or depressed at the center or nearly funnel-shaped, smooth, smoky or gray with a saturated watery appearance, light gray or nearly white when dry. The =gills= are narrow, crowded, or a little decurrent. The slender =stem= is smooth, hollow, equal. Figure 104 is from plants (No. 3373, C. U. herbarium) collected in woods near Ithaca, N. Y., in the autumn of 1899. PLEUROTUS Fr. [Illustration: FIGURE 105.--Pleurotus ulmarius. Cap white, or with shades of yellow or brown near the center (natural size). Copyright.]