veil which stretches across from the stem to the margin of the 
cap. These young plants are called “button mushrooms.” As 
the plant develops and the cap expands, the edge of the veil sepa- 
rates from the margin of the cap, but still adheres to the stem, 
and forms the ring or collar. The cap, when fully expanded, is 
broadly convex, or nearly flat above. It is generally adorned 
with silky fibrils, but sometimes these are collected in such a way 
as to form little bundles or scales, which, however, are usually 
scarcely noticeable. In old age they have often vanished, and 
the cap appears quite smooth. Its margin generally extends 
slightly beyond the outer extremity of the gills. 
The color of the cap varies from pure white to brown or 
tawny brown. The flesh is white. The gills, when first revealed 
by the separation of the veil, are of a delicate pale pink hue, but 
with advancing age this gradually deepens, and finally turns to 
a dark brown or blackish-brown color. In dried specimens the 
color might easily be called black. 
The stem is rather short—scarcely as long as the cap is broad. 
It is nearly cylindrical, 7. ¢., about as thick at the top as at the 
bottom, and its color is white or whitish. The substance in the 
centre is a little softer or more spongy than toward the exterior, 
and for this reason the stem is described as “stuffed,” as if it were 
filled with a pith. Sometimes the collar shrivels so much that it 
is scarcely perceptible in old plants, or it may even disappear en- 
tirely. The spores are brown in the mass. They are sometimes 
described as purplish-brown, but I never could detect any pur- 
plish tint in them or in the gills. 
This mushroom, like many other plants that have been long 
and extensively cultivated, has developed into several varieties, 
which exhibit quite well marked distinctive features. 
The White variety, var. albus, has the cap and stem white, the 
cap silky and the stem short. This is our most common wild 
form, and it is also cultivated. 
The Gray variety, var. griseus, has the cap gray, silky and 
shining. J have seen this from Virginia only. 
The Garden variety, var. hortensis, has the cap brownish, or 
almost tawny brown, and fibrillose, or marked with obscure 
scales. This variety is often cultivated, but rarely found wild. 
Several other varieties are recorded as European, but I have 
seen none of them in this country. 
Generally the cap of the Common mushroom is two to four 
inches broad, the stem one to three inches long, and one-third to 
two-thirds of an inch thick. Its most frequent place of growth is 
27 
