32 BULLETIN" 175, U. S. DEPAETMENT OF AGRICULTURE. 



Cap 5 lines to three-fourths inch broad; stem 2 to 4 inches long. (PI. II, fig. 2; from 

 F. E. Clements.) 



This little fungus is very common in lawns or in richly manured places, where it 

 appears early in the spring and persists until frost. It exhibits considerable variation 

 in size and color, the latter ranging from light tan to brown and depending upon con- 

 ditions of humidity. The species is small but tender and can be preserved for winter 

 use by drying. 



AGARICUS. 



The genus Agaricus is characterized by brown or blackish spores 

 with a purplish tinge and by the presence of a ring. The cap is 

 mostly fleshy and the gills are free from the stem. The genus is 

 closely related to Stropharia, but separated from it by the free gills 

 and the noncontinuity of the stem and the cap. The species of Agari- 

 cus occur in pastures, meadows, woods, and manured ground. All 

 are edible, but certain forms are of especially good flavor. Bright 

 colors are mostly absent and white or dingy brown shades predomi- 

 nate. 



Agaricus arvensis. Horse or field mushroom. (Edible.) 



Cap convex, bell shaped, then expanded, when young floccose or mealy, later 

 smooth, white or yellowish; flesh white; gills white to pink, at length blackish brown, 

 free, close, may be broader toward the stem; stem stout, hollow or stuffed, maybe 

 slightly bulbous, smooth; ring rather large, thick, the upper part white, membrana- 

 ceous, the lower yellowish and radially split. 



Cap 3 to 5 inches broad; stem 2 to 5 inches high, 4 to 10 lines thick. 



Agaricus arvensis is to be found in fields, pastures, and waste places. It is closely 

 related to the ordinary cultivated mushroom, but differs in its larger size and double 

 ring. It is an excellent edible species, the delicacy of flavor and texture largely 

 depending, like other mushrooms, upon its age. 



Agaricus campestris. Common or cultivated mushroom. (Edible.) 



Cap rounded, convex, when expanded nearly plane, smooth, silky floccose or 

 squamulose, white or light brown, squamules brown, margin incurved; flesh white, 

 firm; gills white in the button stage, then pink, soon becoming purplish brown, dark 

 brown, or nearly black, free from the stem, rounded behind, subdeliquescent; stem 

 white, subequal, smooth or nearly so; veil sometimes remaining as fragments on the 

 margin of cap; ring frail, sometimes soon disappearing. 



Cap 1^ to 4 inches broad; stem 2 to 3 inches long, 4 to 8 lines thick. (PI. XIII, 

 fig. 3.) 



This is the most common and best known of all the edible mushrooms. It is a spe- 

 cies of high commercial value, lending itself to very successful and profitable artificial 

 cultivation. It is cosmopolitan in its geographical distribution, being as universally 

 known abroad as in America. It is cultivated in caves, cellars, and in especially con- 

 structed houses; but it also occurs abundantly in the wild state, appearing in pastures, 

 grassy places, and richly manured ground. The only danger in collecting it in the 

 wild form is in mistaking an Amanita for an Agaricus; however, this danger may be 

 obviated by waiting until the gills are decidedly pink before collecting the mush- 

 rooms. 



Agaricus placomyces. Flat-cap mushroom. (Edible.) 



Cap thin, at first broadly ovate, convex or expanded and flat in age, whitish, adorned 

 with numerous minute, brown scales, which become crowded in the center, forming 

 a large brown patch; gills close, white, then pinkish, finally blackish brown; veil 



