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..
The annulus or ring on the stem of the ink-cap is very different from that of the shaggy-mane. It forms an irregularly zigzag elevated line of threads which extend around the stem near the base. It is well shown in Fig. 41 as a border line between the lower scaly end of the stem and the smooth white upper part. It is formed at the time of the separation of the margin of the cap from the stem, the connecting fibres being pulled outward and left to mark the line of junction, while others below give the scaly appearance. It is easily effaced by rough handling or by the washing of the rains. A section of a plant is illustrated by a photograph in Fig. 42. On either side of the stem is shown the layer of fibres which form the annulus, and this layer is of a different texture from that of the stem. The stem is hollow as seen here also. In this figure one can see the change in color of the gills just at the time when they begin to deliquesce. This deliquescence proceeds much in the same way as in the shaggy-mane, and sometimes the thin remnant of the cap expands and the margin is enrolled over the top.
Coprinus atramentarius, showing annulus as border line between scaly and smooth part of the stem (natural size).
Coprinus micaceus (Bull.) Fr. Edible. - The glistening coprinus received its name because of the very delicate scales which often cover the surface of the cap, and glisten in the light like particles of mica. This plant is very common during the spring and early summer, though it does appear during the autumn. It occurs about the bases of stumps or trees or in grassy or denuded places, from dead roots, etc., buried in the soil. It occurs in dense tufts of ten to thirty or more individuals; sometimes as many as several hundred spring up from the roots of a dead tree or stump along the streets or in lawns, forming large masses. More rarely it occurs on logs in the woods, and sometimes the plants are scattered in lawns. From the different habits of the plant it is sometimes difficult to determine, especially where the individuals are more or less scattered. However, the color, and the markings on the cap, especially the presence of the small shining scales when not effaced, characterize the plant so that little difficulty is experienced in determining it when one has once carefully noted these peculiarities. Figure 43 is from a group of three young individuals photo-graphed just as the margin of the pileus is breaking away from the lower part of the stem, showing the delicate fibrous ring which is formed in the same way as in Coprinus atramen-tarius. The ring is much more delicate and is rarely seen except in very young specimens which are carefully collected and which have not been washed by rains. The mature plants are 8-10 cm. high (3-4 inches), and the cap varies from 2-4 cm. in diameter. The stem is quite slender and the cap and gills quite thin as compared with the shaggy-mane and ink-cap. The gills are not nearly so crowded as they are in the two other species. The cap is tan color, or light buff, or yellowish brown. Except near the center it is marked with quite prominent striations which radiate to the margin. These striations are minute furrows or depressed lines, and form one of the characters of the species, being much more prominent than on the cap of the ink-cap.
Coprinus atramentarius, section of one of the plants in Fig. 41 (natural size).
Coprinus micaceus, young stage showing annulus, on the cap the "mica" particles (natural size).
In wet weather this coprinus melts down into an inky fluid also, but in quite dry weather it remains more or less firm, and sometimes it does not deliquesce at all, but dries with all parts well preserved, though much shrunken of course, as is the case with all the very fleshy fungi.
Coprinus micaceus, plants natural size, from floor of coal mine at Wilkesbarre. Caps tan color. Copyright.
Plate 11, Figure 45
Panaeolus retirugis, group of plants from lawn along street, showing veil in young plants at the left, which breaks into V-shaped loops and clings to margin of the cap. Cap dark smoky color at first, becoming grayish in age (natural size). Copyright.