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..
There is one curious feature about the expansion of the pileus of the shaggy-mane which could not escape our attention. The pileus has become very long while comparatively little lateral expansion has taken place. The pileus has remained cylindrical or barrel-shaped, while in the case of the common mushroom the pileus expands into the form of an umbrella.
The cylindrical or barrel-shaped pileus is characteristic of the shaggy-mane mushroom. As the pileus elongates the stem does also, but more rapidly. This tears apart the connection of the margin of the pileus with the base of the stem, as is plainly shown in Fig. 33. In breaking away, the connecting portion or veil is freed both from the stem and from the margin of the pileus, and is left as a free, or loose, ring around the stem. In the shaggy-mane the veil does not form a thin, expanded curtain. It is really an annular outer layer of the button lying between the margin of the cap and the base of the stem. It becomes free from the stem. As the stem elongates more rapidly than the cap, the latter is lifted up away from the base of the stem.
Coprinus comatus, early stages of deliquescence; the ring is lying on the sod (natural size).
packed side by side. They are nowhere attached to the stem, but at the upper end round off to the cap, leaving a well defined space between their ends and the stem. The cap, while it is rather thick at the center, i. e., where it joins the stem, becomes comparatively thin where it spreads out over the gills. At this age of the plant the gills are of a rich salmon color, i. e., before the spores are ripe, and the taste when raw is a pleasant nutty flavor, reminding one of the meat of fresh green hickory nuts. In a somewhat earlier stage the edges of all the gills are closely applied to the stem which they surround. So closely are they applied to the stem in most cases that threads of mycelium pass from the stem to the edge of the gills. As the cap expands slightly in ageing, these threads are torn asunder and the stem is covered with a very delicate down or with flocculent particles which easily disappear on handling or by the washing of the rains. The edges of the gills are also left in a frazzled condition, as one can see by examining them with a good hand lens.
The spores now begin to ripen and as they become black the color of the gills changes. At the same time the gills and the cap begin to dissolve into an inky fluid, first becoming dark and then melting into a black liquid. As this accumulates it forms into drops which dangle from the cap until they fall away. This change takes place on the margin of the cap first, and advances toward the center, and the contrast of color, as the blackening invades the rich salmon, is very striking. The cap now begins to expand outward more, so that it becomes somewhat umbrella shaped. The extreme outer surface does not dissolve so freely, and the thin remnant curls upward and becomes enrolled on the upper side as the cap with wasted gills becomes nearly flat.
Coprinus atramentarius (Bull.) Fr. Edible. - The ink-cap (Copri-nus atramentarius) occurs under much the same conditions as the shaggy-mane, and is sometimes found accompanying it. It is usually more common and more abundant. It springs up in old or newly made lawns which have been richly manured, or it occurs in other grassy places. Sometimes the plants are scattered, sometimes two or three in a cluster, but usually large clusters are formed where ten to twenty or more are crowded closely together (Fig. 39). The stems are shorter than those of the shaggy-mane and the cap is different in shape and color. The cap is egg-shaped or oval. It varies in color from a silvery grey, in some forms, to a dark ashen grey, or smoky brown color in others. Sometimes the cap is entirely smooth, as 1 have seen it in some of the silvery grey forms, where the delicate fibres coursing down in lines on the outer surface cast a beautiful silvery sheen in the light. Other forms present numerous small scales on the top or center of the cap which are formed by the cleavage of the outer surface here into large numbers of pointed tufts. In others, the delicate tufts cover more or less the entire surface, giving the plant a coarsely granular aspect. This is perhaps the more common appearance, at least so far as my observation goes. But not infrequently one finds forms which have the entire outer surface of the cap torn into quite a large number of coarse scales, and these are often more prominent over the upper portion. Fine lines or striations mark also the entire surface of all the forms, especially toward the margin, where the scales are not so prominent. The marginal half of the cap is also frequently furrowed more or less irregularly, and this forms a crenate or uneven edge.
Plate 9, Figure 38
Coprinus comatus, drops of inky fluid about to fall from wasted pileus (natural size).
Plate 10, Figure 39
Coprinus atranrientarius, nearly smooth form, gray color (natural size).
Coprinus atramentarius, scaly form (natural size).