This section is from the book "Studies of American Fungi: Mushrooms, Edible, Poisonous, Etc.", by George Francis Atkinson. Also available from Amazon: Studies of American Fungi: Mushrooms, Edible, Poisonous, Etc..
Marasmius cohaerens (Fr.) Bres. (Mycena cohcerens Fr. Collybia lach-nophylla Berk. Collybia spimilifera 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 cohœrens 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 cystida 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 x 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. her-barium) 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 setae or cystidia.
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).
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.