=Mycena acicula= Schaeff.--This is one of the very small mycenas, and with the brilliant red pileus and yellow gills and stem it makes a very pretty object growing on leaves, twigs, or rotten wood in the forest. It occurs during summer and autumn. It is 2--5 cm. high, the cap 2--4 mm.

broad, and the stem is thread-like.

[Ill.u.s.tration: FIGURE 100.--Mycena acicula. Cap brilliant red, gills and stem yellowish (natural size). Copyright.]

The =pileus= is very thin, membranaceous, bell-shaped, then convex, when the pointed apex appears as a small umbo. It is smooth, striate on the margin, and of a rich vermilion or orange color. The =gills= are rounded at the stem and adnexed, rather broad in the middle, distant, yellow, the edge white, or sometimes the gills are entirely white. The =stem= is very slender, with a root-like process entering the rotten wood, smooth except the hairs on the root-like process, yellow.

Figure 100 is from plants (No. 2780, C. U. herbarium) collected in a woods near Ithaca. It has been found here several times.

=Mycena cyanothrix= Atkinson.--This is a very pretty plant growing on rotting wood in cl.u.s.ters, often two or three joined at the base, the base of the stem inserted in the rotten wood for 1--2 cm., and the base is clothed with blue, hair-like threads. The plants are 6--9 cm. high, the cap 1--2 cm. broad, and the stem not quite 2 mm. in diameter.

The =pileus= is ovate to convex, viscid when young. The color is bright blue when young, becoming pale and whitish in age, with a tendency to fuscous on the center. The cap is smooth and the margin finely striate.

After the plants have dried the color is nearly uniform ochraceous or tawny. The =gills= are close, free, narrow, white, then grayish white, the edge finely toothed or fimbriate. The =spores= are globose, smooth, 6--9 . The =stem= is slender, hollow, faintly purple when young, becoming whitish or flesh color, flexuous, or nearly straight, even, often two united at the base into a root-like extension which enters the rotten wood. The base of the stem is covered with deep blue mycelium which retains its color in age, but disappears on drying after a time.

Figure 101 is from plants (No. 2382, C. U. herbarium) collected at Ithaca, in woods, June 16, 1898.

=Mycena haematopa= Pers.--This is one of the species of _Mycena_ with a red juice which exudes in drops where wounds occur on the plant. It is easily recognized by its dense cespitose habit, the deep blood red juice, the hollow stem, and the crenate or denticulate sterile margin of the cap. Numbers of the plant occur usually in a single cl.u.s.ter, and their bases are closely joined and hairy. The stems are more or less ascending according to the position of the plant on the wood. The plants are 5--10 cm. high, the cap is 1--2.5 cm. broad, and the stem 2--3 mm.

in thickness.

[Ill.u.s.tration: FIGURE 101.--Mycena cyanothrix. Cap viscid when young, blue, becoming pale and whitish in age, and fuscous in center; gills white; stem faintly purple when young, then flesh color or white, blue, clothed with blue hairs at base (natural size). Copyright.]

The =pileus= is conic, then bell-shaped, and as the margin of the cap expands more appears umbonate, obtuse, smooth, even or somewhat striate on the margin. The color varies from whitish to flesh color, or dull red, and appears more or less saturated with a red juice. The thin margin extends a short distance beyond the ends of the gills, and the margin is then beautifully crenate. The =gills= are adnate, and often extend down on the stem a short distance by a little tooth. The =stem= is firm, sometimes smooth, sometimes with minute hairs, at the base with long hairs, hollow, in color the same as that of the pileus.

[Ill.u.s.tration: FIGURE 102.--Mycena haematopa. Dull red or flesh color, or whitish, a dull red juice exudes where broken or cut, margin of cap serrate with thin sterile flaps (natural size). Copyright.]

The color varies somewhat, being darker in some plants than in others.

In some plants the juice is more abundant and they bleed profusely when wounded, while in other cases there is but little of the juice, sometimes wounds only showing a change in color to a deep red without any free drops exuding. Figure 102 is from plants collected at Ithaca, in August, 1899. It is widely distributed in Europe and North America.

=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.

[Ill.u.s.tration: 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 cl.u.s.tered, 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.

[Ill.u.s.tration: 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.

[Ill.u.s.tration: FIGURE 105.--Pleurotus ulmarius. Cap white, or with shades of yellow or brown near the center (natural size). Copyright.]

The genus _Pleurotus_ is usually recognized without difficulty among the fleshy, white-spored agarics, because of the eccentric (not quite in the center of the pileus) or lateral stem, or by the pileus being attached at one side in a more or less shelving position, or in some species where the upper side of the pileus lies directly against the wood on which the plant is growing, and is then said to be _resupinate_. The gills are either decurrent (extending downward) on the stem, or in some species they are rounded or notched at the junction with the stem. There is no annulus, though sometimes a veil, and the genus resembles both _Tricholoma_ and _c.l.i.tocybe_, except for the position of the stem on the pileus. In _Tricholoma_ and _c.l.i.tocybe_ the stem is usually attached at the center, and the majority of the species grow on the ground, while the species of _Pleurotus_ are especially characterized by growing on wood. Some species, at least, appear to grow from the ground, as in Pleurotus petaloides, which is sometimes found growing on buried roots or portions of decayed stumps which no longer show above ground. On the other hand species of _c.l.i.tocybe_, as in C. candida (Fig. 91), often have an eccentric stem. This presents to us one of the many difficulties which students, especially beginners, of this group of fungi meet, and also suggests how unsatisfactory any arrangement of genera as yet proposed is.

=Pleurotus ulmarius= Bull. =Edible.=--The elm pleurotus is so called because it is often found growing on dead elm branches or trunks, or from wounds in living trees, but it is not confined to the elm. It is a large species, easily distinguished from the oyster agaric and the other related species by its long stem attached usually near the center of the cap, and by the gills being rounded or notched at their inner extremity.

The cap is 5--12 cm. broad, the stem 5--10 cm. long, and 1--2 cm. in thickness.

[Ill.u.s.tration: FIGURE 106.--Pleurotus ulmarius. Under view and section (natural size). Copyright.]

The =pileus= is convex, the margin incurved, then nearly expanded, smooth, firm, white or whitish, or with shades of yellow or brown on the center, and the flesh is white. The =gills= are broad, rather distant, sinuate, white or nearly so. The =spores= are globose, 5--8 in diameter. The =stem= is firm, eccentric, usually curved because of its lateral attachment on the side of the tree, and the horizontal position of the pileus.

The elm pleurotus has been long known as an edible fungus, and is regarded as an excellent one for food on account of its flavor and because of its large size. It occurs abundantly during the late autumn, and at this season of the year is usually well protected from the attacks of insects. It occurs in the woods, or fields, more frequently on dead trees. On shade trees which have been severely pruned, and are nearly or quite dead, it sometimes appears at the wounds, where limbs have been removed, in great abundance. In the plants shown in Fig. 105 the stems are strongly curved because the weight of the cap bore the plant downward. Sometimes when the plant is growing directly on the upper side of a branch or log, the stem may be central.

=Pleurotus ostreatus= Jacq. =Edible.=--This plant is known as the oyster agaric, because the form of the plant sometimes suggests the outline of an oyster sh.e.l.l, as is seen in Fig. 107. It grows on dead trunks and branches, usually in crowded cl.u.s.ters, the caps often overlapping or imbricated. It is large, measuring 8--20 cm. or more broad.

The =pileus= is elongated and attached at one side by being sessile, or it is narrowed into a very short stem. It is broadest at the outer extremity, where it becomes quite thin toward the margin. It is more or less curved in outline as seen from the side, being depressed usually on the upper side near the point of attachment, and toward the margin convex and the margin incurved. The color is white, light gray, buff or dark gray, often becoming yellowish on drying. The =gills= are white, broad, not much crowded, and run down on the stem in long elevated lines resembling veins, which anastomose often in a reticulate fashion. The =spores= are white, oblong, 7--10 long. The =stem= when present is very short, and often hairy at the base.

The oyster agaric has long been known as an edible mushroom, but it is not ranked among the best, because, like most _Pleuroti_, it is rather tough, especially in age. It is well to select young plants. Figure 107 is from plants (No. 2097, C. U. herbarium) collected at Ithaca, N. Y.

[Ill.u.s.tration: PLATE 34, FIGURE 107.--Pleurotus ostreatus. Under view showing decurrent and anastomosing gills on the stem. Cap white, light gray, buff, or dark gray in color. Spores white (natural size, often larger). Copyright.]

=Pleurotus sapidus= Kalchb. =Edible.=--This plant usually grows in large cl.u.s.ters from dead trunks or branches or from dead portions of living trees. It grows on a number of different kinds of trees. The stems are often joined at the base, but sometimes the plants are scattered over a portion of the branch or trunk. The cap is from 5--10 cm. broad.

The plants occur from June to November.

[Ill.u.s.tration: PLATE 35, FIGURE 108.--Pleurotus sapidus. Color of cap white, yellowish, gray, or brownish, with lilac tints sometimes. Spores lilac tinted in ma.s.s (1/2 natural size). Copyright.]

The =pileus= is convex, the margin incurved when young, and more or less depressed in age, smooth, broadened toward the margin and tapering into the short stem, which is very short in some cases and elongated in others. Often the caps are quite irregular and the margin wavy, especially when old. It is quite firm, but the margin splits quite readily on being handled. The color varies greatly, white, yellowish, gray, or brownish and lilac tints. The flesh is white. The =stems= are usually attached to the pileus, at or near one edge. The =gills= are white, broad, not at all crowded, and extend down on the stem as in the oyster agaric. They are white or whitish, and as in the other related species are sometimes cracked, due probably to the tension brought to bear because of the expanding pileus. The =spores= are tinged with lilac when seen in ma.s.s, as when caught on paper. The color seems to be intensified after the spores have lain on the paper for a day or two.

It is very difficult to distinguish this species from the oyster agaric.

The color of the spores seems to be the only distinguishing character, and this may not be constant. Peck suggests that it may only be a variety of the oyster agaric. I have found the plant growing from a dead spot on the base of a living oak tree. There was for several years a drive near this tree, and the wheels of vehicles cut into the roots of the tree on this side, and probably so injured it as to kill a portion and give this fungus and another one (_Polystictus pergamenus_) a start, and later they have slowly encroached on the side of the tree.

Figure 108 represents the plant (No. 3307, C. U. herbarium) from a dead maple trunk in a woods near Ithaca, collected during the autumn of 1899.

This plant compares favorably with the oyster agaric as an edible one.

Neither of these plants preserve as well as the elm pleurotus.

=Pleurotus dryinus= Pers. =Edible.=--_Pleurotus dryinus_ represents a section of the genus in which the species are provided with a veil when young, but which disappears as the pileus expands. This species has been long known in Europe on trunks of oak, ash, willow, etc., and occurs there from September to October. It was collected near Ithaca, N. Y., in a beech woods along Six-mile creek, on October 24th, 1898, growing from a decayed knothole in the trunk of a living hickory tree, and again in a few days from a decayed stump. The pileus varies from 5--10 cm. broad, and the lateral or eccentric stem is 2--12 cm. long by 1--2 cm. in thickness, the length of the stem depending on the depth of the insertion of the stem in a hollow portion of the trunk. The plant is white or whitish, and the substance is quite firm, drying quite hard.

The =pileus= is convex to expanded, more or less depressed in the center, the margin involute, and the surface at first floccose, becoming in age floccose scaly, since the surface breaks up into triangular scales more prominent in and near the center, smaller and inconspicuous toward the margin. The prevailing color is white, but in age the scales become cream color or buff (in European plants said to become fuscous).

The pileus is either definitely lateral (Fig. 109) or eccentric when the stem is attached near the center as in Fig. 110. The =gills= are white, becoming tinged with yellow in age, decurrent (running down on the stem) in striae for short distances, 4--5 mm. broad, not crowded. The =stem= is nearly central (Fig. 110), or definitely lateral (Fig. 109), the length varying according to conditions as stated above. It is firm, tough, fibrous. The =veil= is prominent in young and medium plants, floccose, tearing irregularly as the pileus expands.

Figure 110 is from plants (No. 2478a C. U. herbarium) growing from knothole in living hickory tree, and Fig. 109 from plants (No. 2478b) growing on a dead stump, near Ithaca.

According to the descriptions of _P. dryinus_ as given by Persoon, and as followed by Fries and most later writers, the pileus is definitely lateral, and more or less dimidiate, while in _P. corticatus_ Fr., the pileus is entire and the stem rather long and eccentric. Stevenson suggests (p. 166) that corticatus is perhaps too closely allied to dryinus. The plants in our Fig. 110 agree in all respects with _P.

corticatus_, except that possibly the lamellae do not anastomose on the stem as they are said to in _corticatus_. According to the usual descriptions _corticatus_ is given as the larger species, while Fig. 109 of our plant, possessing the typical characters of _dryinus_, is the larger. The form of the pileus, the length and position of the stem, depends, as we know, to a large extent on the position of the plant on the tree. When growing from the upper side, so that there is room above for the expansion of the cap, the pileus is apt to be more regular, just as is the case in _Pleurotus ulmarius_, and the stem more nearly central. When the plant grows from a hollow place in the trunk as those shown in Fig. 110 did, then there is an opportunity for them to grow more or less erect, at least until they emerge from the hollow, and then the pileus is more nearly equal in its expansion and the stem is longer.

Berkeley describes specimens of P. dryinus with long stems growing from a hollow in an ash, and Stevenson (p. 167) reports the same condition.

[Ill.u.s.tration: PLATE 36, FIGURE 109.--Pleurotus dryinus. Side and upper view. Plant entirely white, scales sometimes buff or cream colored in age (natural size). Copyright.]

=Pleurotus sulfureoides= Pk.--This rare species, first collected in the Catskill Mountains 1869, and described by Peck in the 23rd Report, N. Y.

State Mus., p. 86, 1870, was found by me on two different occasions at Ithaca, N. Y., during the autumn of 1898, on rotting logs, Ithaca Flats, and again in Enfield Gorge, six miles from Ithaca. The plants are from 5--8 cm. high, the cap 3--5 cm. broad, and the stem 5--7 mm. in thickness, and the entire plant is of a dull, or pale, yellow.