No. 3.] HYMENIALES OF CONNECTICUT. 



13 



Fruiting-snrface of prominent folds (gills), or with 

 evident leaf-like expansions or plates, which are 

 free or regularly forked, or are united by running 

 together irregularly only at the base or point of at- 

 tachment to the pileUS AGARICACEyE 



AGARICACE^ Fries. Gill-bearing Fungi. 



This family contains by far the largest number of species 

 of mushrooms. They are distinguished by a more or less flat- 

 tened pileus, or cap, which may become convex, bell-shaped, 

 or funnel-shaped; the stem, or stipe, is generally attached to 

 the center, or nearly so, of the under side of the pileus ; or the 

 point of attachment may be at one side, when the pileus be- 

 comes shelving; the stem may be absent and the pileus at- 

 tached directly to the mycelium (sessile). 



The spore-bearing surface is usually on the under side of 

 the pileus, and consists of radiating gills, prominent folds, or 

 veins. Microscopical examination shows these fruiting-sur- 

 faces to be covered with peculiar reproductive cells, or basidia. 

 From each of these basidia, one-celled spores, usually four in 

 number, are produced. 



CHARACTERISTICS OF MUSHROOMS. 



In order that the various parts of a mushroom may be 

 clearly understood, the following explanation is given. 



The fleshy fruit-body of the Agaricaceas is known as the 

 pileus, or cap. Microscopical examination shows it to dififer 

 considerably from the fruit-bodies of the higher plants. There 

 is no cellular tissue, but the structure is composed of inter- 

 woven hollow tubes, technically termed hyphce. These hyphcc 

 serve to conduct the food substances from the basal threads, 

 which resemble the hyphge, to the more highly specialized re- 

 productive cells, the basidia. These hyphal threads which 

 run through the center of the fruit-body, stem, cap, and gills, 

 constitute what is technically known as the trama. When 

 these hyphal threads approach the outer part of the gills, cer- 

 tain specialized cells arise which are spoken of as the suh- 

 hyineinal layer, and from these cells the reproductive cells, or 

 basidia, develop. The basidia, placed closely side by side, con- 



