Studies of American Fungi. Mushrooms, Edible, Poisonous, etc. George Francis Atkinson

volva or outer veil appear on the surface of the cap in rather broad patches, or it may be broken up into a number of smaller ones quite evenly distributed over the surface of the cap. The presence or absence of these scales on the cap depends entirely on the way in which the volva ruptures. When there is a clean rupture at the apex the pileus is free from scales, but if portions of the apex of the volva are torn away they are apt to remain on the cap.

      Plate 14, Figure 56.—Amanita phalloides, brownish, umber, or olive-brown form (natural size). Caps brownish or whitish, and streaked with brown, scales white, gills and stem white, stem slowly turning dull brown where bruised. Copyright.

      The white form is common in this country, and so is the olive or umber form. The yellow form is rarer. Sometimes there is only a tinge of yellow at the center of the white pileus, while in other cases a large part of the pileus may be yellow, a deeper shade usually on the center. The green form is probably more common in Europe than in this country. The olive form varies considerably also in the depth of the color, usually darker on the center and fading out to light olive or gray, or whitish, on the margin. In other cases the entire pileus may be dark olive or umber color. The gills in all the forms are white, and free from the stem or only joined by a narrow line. The stem is stuffed when young, but in age is nearly or quite hollow. It is cylindrical, 6–20 cm. long × 6–12 mm. in thickness. In the larger specimens the bulb is quite prominent and abrupt, while in the smaller specimens it is not always proportionally so large. The stem is usually smooth and the color is white, except in the dark forms, when it is dingy or partakes more or less of the color of the pileus, though much lighter in shade. There is a tendency in these forms to a discoloration of the stem where handled or bruised, and this should caution one in comparing such forms with the edible A. rubescens.

      Figure 57.—Amanita phalloides, volva circumscissile, cap scaly, limb of volva not prominent, cap dark, scales white (natural size). Copyright.

      Perhaps no part of the plant is more variable than the outer veil or volva. Where the volva is quite thick and stout it usually splits at the apex, and there is a prominent free limb, as shown in Fig. 55. Sometimes thin portions of the volva are caught, and remain on the surface of the pileus. But when the volva is thinner and of a looser texture, it splits transversely about the middle, circumscissile, and all or a large part of the upper half of the volva then clings to the cap, and is separated into patches. Between this and the former condition there seem to be all gradations. Some of these are shown in Fig. 56, which is from a photograph of dark olive and umber forms, from plants collected in the Blue Ridge mountains, at Blowing Rock, N. C., during September, 1899. In the very young plant the volva split transversely (in a circumscissile fashion) quite clearly, and the free limb is quite short and distant from the stem on the margin of the saucer-like bulb. In the large and fully expanded plant at the center, the volva ruptured irregularly at the apex, and portions of the thin upper half remain as patches on the cap while the larger part remains as the free limb, attached at the margin of the broad saucer-shaped bulb, and collapsed up against the base of the stem.

      Figure 58.—Amanita phalloides, volva circumscissile, concave bulb margined by definite short limb of volva; upper part of volva has disappeared from cap; cap whitish, tinged with brown.

      Figure 58 and the small plant in Fig. 56, both from photographs of the sooty form of Amanita phalloides, show in a striking manner the typical condition of the circumscissile volva margining the broad saucer-like bulb as described for Amanita mappa. The color of A. mappa is usually said to be straw color, but Fries even says that the color is as in A. phalloides, "now white, now green, now yellow, now dark brown" (Epicrisis, page 6). According to this, Fig. 58 would represent A. mappa.

      The variable condition in this one species A. phalloides, now splitting at the apex, now tearing up irregularly, now splitting in a definitely circumscissile manner, seems to bid defiance to any attempt to separate the species of Amanita into groups based on the manner in which the volva ruptures. While it seems to be quite fixed and characteristic in certain species, it is so extremely variable in others as to lead to the suspicion that it is responsible in some cases for the multiplication and confusion of species. At the same time, the occurrence of some of these forms at certain seasons of the year suggests the desirability of prolonged and careful study of fresh material, and the search for additional evidence of the unity of these forms, or of their definite segregation.

      Figure 59.—Amanita verna, white (natural size). Copyright.

      Since the Amanita phalloides occurs usually in woods, or along borders of woods, there is little danger of confounding it with edible mushrooms collected in lawns distant from the woods, and in open fields. However, it does occur in lawns bordering on woods, and in the summer of 1899 I found several of the white forms of this species in a lawn distant from the woods. This should cause beginners and those not thoroughly familiar with the appearance of the plant to be extremely cautious against eating mushrooms simply because they were not collected in or near the woods. Furthermore, sometimes the white form of the deadly amanita possesses a faint tinge of pink in the gills, which might lead the novice to mistake it for the common mushroom. The bulb of the deadly amanita is usually inserted quite deep in the soil or leaf mold, and specimens are often picked leaving the very important character of the volva in the ground, and then the plant might easily be taken for the common mushroom, or more likely for the smooth lepiota, Lepiota naucina, which is entirely white, the gills only in age showing a faint pink tinge. It is very important, therefore, that, until one has such familiarity with these plants that they are easily recognized in the absence of some of these characters, the stem should be carefully dug from the soil. In the case of the specimens of the deadly amanita growing in the lawn on the campus of Cornell University, the stems were sunk to three to four inches in the quite hard ground.

      Amanita verna Bull. Deadly Poisonous.—The Amanita verna is by some considered as only a white form of the Amanita phalloides. It is of a pure white color, and this in addition to its very poisonous property has led to its designation as the "destroying angel."

      Figure 60.—Amanita verna, "buttons," cap bursting through the volva; left hand plant in section (natural size). Copyright.

      The pileus is smooth and viscid when moist; the gills free; the stem stuffed or hollow in age; the annulus forms a broad collar, and the volva is split at the apex, and being quite stout, the free limb is prominent, and it hugs more or less closely to the base of the stem. Figure 59 represents the form of the plant which Gillet recognizes as A. verna; the pileus convex, the annulus broad and entire, and the stem scaly. These floccose scales are formed as a result of the separation of the annulus from the outer layer of the stem.

      The characters presented in the formation of the veil and annulus in this species are very interesting, and sometimes present two of the types in the formation of the veil and annulus found in the genus Amanita. In the very young plant, in the button stage, as the young gills lie with their edges close against the side of the stem, loose threads extend from the edges of the gills to the outer layer of the stem.