222 
Mycologia 
stipe can usually be traced to a dead root, from which the plant 
derives its chief supply of nourishment. 
Agaricus arvensis Schaeff. 
Horse Mushroom. Field Mushroom 
Plate 137. Figure 2. X 1 
Pileus large, convex, 6-15 cm. broad; surface white, becoming 
yellowish with age or on drying; context white, thick, highly fla- 
vored and easily digested ; lamellae white to pale-pinkish at first, 
at length brown; spores ellipsoid, smooth, brown, 9-11X6,11; 
stipe long, white, often enlarged at the base, 5-10 cm. long, 8-16 
mm. thick ; annulus of two parts, membranous and white above, 
radiately split and tinged with yellow below. 
This species grows in rich soil in pastures, fields, and wood 
borders from midsummer to early fall. It resembles the common 
mushroom, but is larger, with longer stipe, paler lamellae, and a 
peculiar double annulus. I have often eaten it in Sweden and 
found it delicious. The slender, wood-loving Agaricus silvicola 
can hardly be distinguished from it at times. 
Agaricus silvicola Vitt. 
Forest Mushroom 
P late 139. X V2 
Pileus convex or expanded, 5-12 cm. broad, all parts of the 
plant except the lamellae being white at first and becoming tinged 
with straw-color in places with age or almost entirely on drying; 
surface smooth, glabrous or slightly silky; context white; lamel- 
lae thin, close, rounded behind, free, pale-reddish-gray when 
young, becoming darker with age, and finally brown or blackish- 
brown with a chestnut tint ; spores ellipsoid, brown, 7.5 X 4 m ; 
stipe long, equal, smooth, stuffed or hollow, bulbous, white, 10-20 
cm. long and 6-10 mm. thick; veil usually single, forming a thin, 
membranous annulus decorated with floccose patches below. 
This beautiful edible species is of wide distribution, but unfor- 
tunately not very abundant. It occurs in open woods and wood 
borders, in rich soil or vegetable mold. Its smaller size and more 
simple veil distinguish it from A. arvensis. 
