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..
This species is rather common and widely distributed, occurring in grassy places recently manured, or on dung. The plants are scattered or clustered, rarely two or three joined at the base. They are 5-12 cm. high, the cap 1-3 cm. broad, and the stems 2-4 mm. in thickness. The entire plant is light yellow, and viscid when moist, the gills becoming purplish brown, or nearly black. Stevenson says it is regarded as poisonous.
Stropharia semiglobata (natural size). Cap and stem light yellow, viscid; gills brownish-purple. Copyright.
The pileus is rounded, then hemispherical (semi-globate), smooth, fleshy at the center, thinner toward the margin, even, very viscid or viscous when moist, light yellow. The gills are squarely set against the stem (adnate), broad, smooth, in age purplish brown to blackish, the color more or less clouded. The spores in mass, are brownish purple. The stem is slender, cylindrical, becoming hollow, straight, even or bulbous below, yellowish, but paler at the apex where there are often parallel striae, marks from the gills in the young stage. The stem is often viscid and smeared with the glutinous substance which envelopes the plant when young, and from the more or less glutinous veil. The ring is glutinous when moist.
Figure 30 is from plants (No. 4613 C. U. herbarium) collected on one of the streets of Ithaca.
Stropharia stercoraria Fr., is a closely related plant, about the same size, but the pileus, first hemispherical, then becoming expanded and sometimes striate on the margin, while the stem is stuffed. The gills are said to be of one color and the ring floccose, viscose, and evanescent in drying. It occurs on dung, or in grassy places recently manured.
Stropharia aeruginosa Curt., the greenish Stropharia, is from 6-8 cm. high, and the pileus 5-7 cm. broad. The ground color is yellowish, but the plant is covered with a greenish slime which tends to disappear with age. It is found in woods and open places during late summer and in autumn. According to Stevenson it is poisonous.