Studies of American Fungi. Mushrooms, Edible, Poisonous, etc.

The =pileus= passes from convex to expanded and nearly flat in age, the margin when mature is marked by depressed lines forming parallel striations, and on the surface are numbers of scattered floccose or rather compact scales, formed from the fragments of the upper part of the volva or outer veil. These scales are usually white in color and are quite easily removed, so that old plants are sometimes quite free from them. The scales are sometimes yellowish in color. The color of the pileus varies from yellow to orange, or even red, the yellow color being more common. Late in the season the color is paler, and in old plants also the color fades out, so that white forms are sometimes found. The flesh is white, sometimes yellowish underneath the cuticle. The =gills= in typical forms are white, in some forms accredited to this species they are yellowish. The =stem= is cylindrical, hollow, or stuffed when young, and enlarged below into a prominent bulb. It is white, covered with loose floccose scales, or more or less lacerate or torn, and the lower part of the stem and upper part of the bulb are marked usually by prominent concentric scales forming interrupted rings. These are formed by the splitting of the outer veil or volva, and form the remnants of the volva present on the base of the stem.

The main features in the development of the plant are shown in Figs. 52--54, where a series from the button stage to the mature plant is represented. In the youngest specimens the outline of the bulb and the young convex or nearly globose cap are only seen, and these are covered with the more or less floccose outer veil or volva. The fungus threads composing this layer cease to grow, and with the expansion of the cap and the elongation of the stem, the volva is torn into patches. The upper and lower surface of the inner veil is attached to the edge of the gills and to the outer surface of the stem by loose threads, which are torn asunder as the pileus expands. Floccose scales are thus left on the surface of the stem below the annulus, as in the left hand plant of Fig. 53. The veil remains attached longer to the gills and is first separated from the stem. Again, as in the right hand plant, it may first be separated from the gills when it is later ripped up from the stem.

The fly agaric is one of the well known poisonous species and is very widely distributed in this country, as well as in other parts of the world. In well developed forms there should be no difficulty in distinguishing it from the common mushroom by even a novice. Nor should there be difficulty in distinguishing it from the royal agaric, or Cæsar's agaric (Amanita cæsarea), by one who has become reasonably familiar with the characters and appearance of the two. But small and depauperate specimens of the two species run so nearly together in form, color, and surface characters, that it becomes a matter of some difficulty for even an expert to distinguish them.

Figures 52--54 are from plants (No. 2065 C. U. herbarium) collected in an open woods near Ithaca. For the poisonous property of the plant see Chapter XX.

=Amanita frostiana= Pk. =Poisonous.=--According to Dr. Peck, who published the first description of this plant, it grows in company with Amanita muscaria, but seems to prefer more dense woods, especially mixed or hemlock woods, and occurs from June to October. The plant is 5--8 cm. high, the caps 2--5 cm. broad, and the stems 3--6 mm. in thickness.

The =pileus= is "convex to expanded, bright orange or yellow, warty, sometimes nearly or quite smooth, striate on the margin; =lamellæ= white or tinged with yellow; =stem= white or yellowish, stuffed, bearing a slight, sometimes evanescent annulus, bulbous at the base, the bulb slightly margined by the volva; spores globose," 7.5--10 µ in diameter. He notes that it appears like a small form of A. muscaria, to which it was first referred as var. minor,--"The only characters for distinguishing it are its small size and its globose spores." It is near A. muscaria var. puella Pers.

I have several times found this plant in the Adirondack mountains, N. Y., and Ithaca, and also at Blowing Rock, N. C. The volva is often yellowish, so that the warts on the pileus are also yellow, and sometimes the only remnants of the volva on the base of the stem are yellow or orange particles. The annulus is also frequently yellow. In our plants, which seem to be typical, the spores are nearly globose, varying to oval, and with the minute point where the spore was attached to the sterigma at the smaller end, the spores usually being finely granular, 6--9 µ in diameter, and rarely varying towards short elliptical, showing a tendency to approach the shape of the spores of A. muscaria. The species as I have seen it is a very variable one, large forms being difficult to separate from A. muscaria, on the one hand, and others difficult to separate from the depauperate forms of A. cæsarea. In the latter, however, the striæ are coarser, though the yellow color may be present only on portions of the pileus. The spores of A. cæsarea are from globose to oval, ovate or short elliptical, the globose ones often agreeing in size with the spores of A. frostiana, but they usually contain a prominent oil drop or "nucleus," often nearly filling the spore. In some specimens of A. frostiana the spores are quite variable, being nearly globose, ovate to elliptical, approaching the spores of A. muscaria. These intermediate forms should not in themselves lead one to regard all these three species as representing variations in a single variable species. With observations in the field I should think it possible to separate them.

=Amanita phalloides= Fr. =Deadly Poisonous.=--The Amanita phalloides and its various forms, or closely related species, are the most dangerous of the poisonous mushrooms. For this reason the A. phalloides is known as the deadly agaric, or deadly amanita. The plant is very variable in color, the forms being pure white, or yellowish, green, or olive to umber. Variations also occur in the way in which the volva ruptures, as well as in the surface characters of the stem, and thus it is often a difficult matter to determine whether all these forms represent a single variable species or whether there are several species, and if so, what are the limits of these species. Whether these are recognized as different forms of one species or as different species, they are all very poisonous. The plant usually occurs in woods or along the borders of woods. It does, however, sometimes occur in lawns. It varies from 6--20 cm. high, the cap from 3--10 cm. broad, and the stem 6--10 mm. in thickness.

The =pileus= is fleshy, viscid or slimy when moist, smooth, that is, not striate, orbicular to bell-shaped, convex and finally expanded, and in old specimens more or less depressed by the elevation of the margin. The cap is often free from any remnants of the volva, while in other cases portions of the 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.

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.

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 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.