MARASMIUS Fr.
In this genus the plants are tough and fleshy or membranaceous, leathery and dry. They do not easily decay, but shrivel up in dry weather, and revive in wet weather, or when placed in water. This is an important character in distinguishing the genus. It is closely related to Collybia, from which it is difficult to separate certain species. On the other hand, it is closely related to Lentinus and Panus, both of which are tough and pliant. In Marasmius, however, the substance of the pileus is separate from that of the stem, while in Lentinus and Panus it is continuous, a character rather difficult for the beginner to understand. The species of Marasmius, however, are generally much smaller than those of Lentinus and Panus, especially those which grow on wood. The stem in Marasmius is in nearly all species central, while in Lentinus and Panus it is generally more or less eccentric. Many of the species of the genus Marasmius have an odor of garlic when fresh. Besides the fairy ring (M. oreades) which grows on the ground, M. rotula is a very common species on wood and leaves. It has a slender, black, shining stem, and a brownish pileus usually with a black spot in the depression in the center. The species are very numerous. Peck, 23rd Report, N. Y. State Mus., p. 124–126, describes 8 species. Morgan Jour. Cinn. Soc. Nat. Hist. 6: 189–194, describes 17 species.
Marasmius oreades Fr. Edible.—This is the well known "fairy ring" mushroom. It grows during the summer and autumn in grassy places, as in lawns, by roadsides, in pastures, etc. It appears most abundantly during wet weather or following heavy rains. It is found usually in circles, or in the arc of a circle, though few scattered plants not arranged in this way often occur. The plants are 7–10 cm. high, the cap 2–4 cm. broad, and the stem 3–4 mm. in thickness.
Figure 129.—Marasmius oreades. Caps buff, tawny, or reddish.
The pileus is convex to expanded, sometimes the center elevated, fleshy, rather thin, tough, smooth, buff color, or tawny or reddish, in age, or in drying, paler. When moist the pileus may be striate on the margin. The gills are broad, free or adnexed, rounded near the stem, white or dull yellowish. The spores are elliptical, 7–8 µ long. The stem is tough, solid, whitish.
This widely distributed fungus is much prized everywhere by those who know it. It is not the only fungus which appears in rings, so that this habit is not peculiar to this plant. Several different kinds are known to appear in rings at times. The appearance of the fungus in rings is due to the mode of growth of the mycelium or spawn in the soil.
Having started at a given spot the mycelium consumes the food material in the soil suitable for it, and the plants for the first year appear in a group. In the center of this spot the mycelium, having consumed all the available food, probably dies after producing the crop of mushrooms. But around the edge of the spot the mycelium or spawn still exists, and at the beginning of the next season it starts into growth and feeds on the available food in a zone surrounding the spot where it grew the previous year. This second year, then, the plants appear in a small ring. So in succeeding years it advances outward, the ring each year becoming larger. Where the plants appear only in the arc of a circle, something has happened to check or destroy the mycelium in the remaining arc of the circle.
It has been noted by several observers that the grass in the ring occupied by the mushrooms is often greener than that adjoining. This is perhaps due to some stimulus exerted by the mycelium of the fungus on the grass, or possibly the mycelium may in some way make certain foods available for the grass which gives an additional supply to it at this point.
Fig. [129] is from plants (No. 5503, C. U. herbarium) collected in a lawn, October 25, 1900, Ithaca.
Illustrations of some fine large rings formed by this fungus appeared in circular No. 13 by Mr. Coville, of the Division of Botany in the U. S. Dept. Agr.
Marasmius cohærens (Fr.) Bres. (Mycena cohærens Fr. Collybia lachnophylla Berk. Collybia spinulifera Pk.)—This plant grows in dense clusters, ten to twenty individuals with their stems closely joined below and fastened together by the abundant growth of threads from the lower ends. From this character the name cohærens was derived. The plants grow on the ground or on very rotten wood in woods during late spring and in the summer. The plant is not very common in this country, but appears to be widely distributed both in Europe and here, having been collected in Carolina, Ohio, Vermont, New York, etc. The plants are 12–20 cm. high, the cap 2–2.5 cm. broad, and the stem 4–7 mm. in thickness.
The pileus is fleshy, tough, convex or bell-shaped, then expanded, sometimes umbonate, or in age sometimes the margin upturned and more or less wavy, not viscid, but finely striate when damp, thin. The color varies from vinaceous cinnamon to chestnut or light leather color, or tawny, paler in age, and sometimes darker on the center. The gills are sometimes more or less crowded, narrow, 5–6 mm. broad, adnate, but notched, and sometimes becoming free from the stem. The color is light leather color, brick red or bay, the color and color variations being due to numbers of colored cystidia or spicules scattered over the surface of the gills and on the edge. The cystidia are fulvous, fusoid, 75–90 µ long. The spores are oval, white, small, 6 × 3 µ. The stem is long and slender, nearly cylindrical, tapering somewhat above, slightly enlarged below, and rooting. The color is the same as that of the pileus or dark bay brown, and shining, and seems to be due to large numbers of spicules similar to those on the gills. The color is paler below in some cases, or gradually darker below in others. The stems are bound together below by numerous threads.
Figure [130] is from plants (No. 2373, C. U. herbarium) collected in woods near Freeville, N. Y. The plants have been collected near Ithaca on three different occasions, twice near Freeville about nine miles from Ithaca, and once in the woods at Ithaca. It is easily distinguished by its color and the presence of the peculiar setæ or cystidia.
Figure 130.—Marasmius cohaerens (Fr.) Bres. (= Mycena cohaerens Fr. = Collybia lachnophylla Berk. = C. spinulifera Pk.) Color chestnut, light leather color, tawny or vinaceous cinnamon, darker in center, stems dark, shining, gills leather color, or fulvous, or wine color, brick red or bay, varying in different specimens (natural size). Copyright.
Although the plant has been collected on several different occasions in America, it does not seem to have been recognized under this name until recently, save the record of it from Carolina by de Schweinitz (Synop. fung. Car. No. 606. p. 81).
LENTINUS Fr.
The plants of this genus are tough and pliant, becoming hard when old, unless very watery, and when dry. The genus differs from the other tough and pliant ones by the peculiarity of the gills, the gills being notched or serrate on the edges. Sometimes this appearance is intensified by the cracking of the gills in age or in drying. The nearest ally of the genus is Panus, which is only separated from Lentinus by the edge of the gills being plane. This does not seem a very good character on which to separate the species of the two genera, since it is often difficult to tell whether the gills are naturally serrate or whether they have become so by certain tensions which exist on the lamellæ during the expansion and drying of the pileus. Schrœter unites Panus with Lentinus (Cohn's Krypt. Flora, Schlesien, 3, 1; 554, 1889). The plants are usually very irregular and many of them shelving, only a few grow upright and have regular caps.
Lentinus vulpinus Fr.—This is a large and handsome species, having a wide distribution in Europe and in this country, but it does not seem to be common. It grows on trunks, logs, stumps, etc., in the woods. It was quite abundant during late summer and in the autumn on fallen logs, in a woods near Ithaca. The caps are shelving, closely overlapping in shingled fashion (imbricated), and joined at the narrowed base. The surface is convex, and the margin is strongly incurved, so that each of the individual caps is shell-shaped (conchate). The surface of the pileus is coarsely hairy or hispid, the surface becoming more rough with age. Many coarse hairs unite to form coarse tufts which are stouter and nearly erect toward the base of the cap, and give the surface a tuberculate appearance. Toward the margin of the cap these coarse hairs are arranged in nearly parallel lines, making rows or ridges, which are very rough. The hairs and tubercles are dark in color, being nearly black toward the base, especially in old plants, and sometimes pale or of a smoky hue, especially in young plants. The pileus is flesh color when young, becoming darker when old, and the flesh is quite thin, whitish toward the gills and darker toward the surface. The gills are broad, nearly white, flesh color near the base, coarsely serrate, becoming cracked in age and in drying, narrowed toward the base of the pileus, not forked, crowded, 4–6 mm. broad. The cap and gills are tough even when fresh. The plant has an intensely pungent taste.
Figures 131, 132 represent an upper, front, and under view of the pilei (No. 3315, C. U. herbarium).
Plate 42, Figure 131.—Lentinus vulpinus. The coarse, hairy scales are black in old plants, paler, of a smoky hue, in younger ones (natural size). Copyright.
Lentinus lecomtei Fr., is a very common and widely distributed species growing on wood. When it grows on the upper side of logs the pileus is sometimes regular and funnel-shaped (cyathiform), but it is often irregular and produced on one side, especially if it grows on the side of the substratum. In most cases, however, there is a funnel-shaped depression above the attachment of the stem. The pileus is tough, reddish or reddish brown or leather color, hairy or sometimes strigose, the margin incurved. The stem is usually short, hairy, or in age it may become more or less smooth. The gills are narrow, crowded, the spores small, ovate to elliptical 5–6 × 2–3 µ. According to Bresadola this is the same as Panus rudis Fr. It resembles very closely also Panus cyathiformis (Schaeff.) Fr., and P. strigosus B. & C.
Lentinus lepideus Fr., [L. squamosus (Schaeff.) Schroet.] is another common and widely distributed species. It is much larger than L. lecomtei, whitish with coarse brown scales on the cap. It is 12–20 cm. high, and the cap is often as broad. The stem is 2–8 cm. long and 1–2 cm. in thickness. It grows on wood.
Figure 132.—Lentinus vulpinus, front and under view (natural size). Copyright.
Lentinus stipticus (Bull.) Schroet. (Panus stipticus Bull.) is a very small species compared with the three named above. It is, however, a very common and widely distributed one, growing on wood, and may be found the year around. The pileus is 1–3 cm. in diameter, whitish or grayish, very tough, expanded in wet weather, and curled up in dry weather. The stem is very short, and attached to one side of the cap. When freshly developed the plant is phosphorescent.