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The FiKLD OK Horse Mushroom (Edibee) 

 Agaricus arrcusis Schaeff. 



The field mushroom, or horse mushroom, occurs in fields or pas- 

 tures, or under trees on lawns, or in the borders of woods. I have 

 found it frecjuently on several different lawns in the city of Urbana. 



The pileus is smooth and dry, the surface sometimes more or less 

 cracked in age, white or sometimes slightly yellowish, convex or con- 

 ical, bell-shaped, and finally expanded. It is 5 to 15 cm. (2 to 6 

 inches) broad. It is usually cjuite thick and firm. 



The gills are quite crowded, free from the stem, and usually broader 

 toward the stem. When very young they are whitish, but as the spores 

 mature they become pinkish and finally blackish brown. The spores 

 are dark purple-brown when viewed in mass. 



The stem is stout, nearly cylindrical or somewhat thickened at the 

 base, smooth, hollow or stuffed, and 5 to 12 cm. (2 to 5 inches) long. 



The ring is rather large and thick and is double, that is, it con- 

 sists of two parts, the upper part being membranous, and the lower 

 part much thicker, often yellowish, and usually split radially so that 

 it remains as patches on the lower surface of the upper memjjrane. In 

 this respect the horse mushroom resembles A. sili'icola and A. pla- 

 comyccs, to both of which it is closely related. 



XMien the stem is first cut there often exudes from the wound a 

 yellowish li(|uid, and the whole plant usually becomes yellowish when 

 dried. 



This plant grows much larger than Agaricus caiiipcstris, and will 

 be found delicious if used in any way in which that mushroom is used. 

 It may be looked for from July to September. It sometimes occurs 

 in large fairy rings, and sometimes is found in considerable (juantities. 

 Even if only a few specimens are found, they may be utilized very 

 well by frying the caps quicklv in a liberal supply of butter and serving 

 on pieces of hot buttered toast. 



Like many other mushrooms, Agaricus ari'cnsis often seems to be 

 partial to the vicinity of trees, though no mycorrhizal or other con- 

 nection with the trees has vet been demonstrated. 



Collected in Champaign county. 



