10 



important class of mushrooms (the Cortinarias) . It is generally white, 

 soft, slightly spongy, cottony, at times fibrillose or even slightly fibrous, 

 again in texture comparable to the spider's web, and may be even 

 powdery or glutinous. It exists intact only in the youth of the plant. 

 It is not visible in the developing mushroom, at least while the cap is 

 closely pressed against the stem, but as the cap expands the membrane 

 extends and finally breaks, leaving in some species its remnants upon the 

 margin of the cap and upon the stem in the usual form of a ring or a mere 

 zone. When the stem is not ringed the veil rises high upon the stalk, 

 sti'etches across to meet the edges of the cap, and is afterwards reflected 

 back over its whole surface. 



MUSHEOOM SPOEES AND MTCELITJM. 



The spore is the reproductive organ of the mushroom. It differs from 

 the seed of the flowering plant in being destitute of an apparent embryo. 

 A seed contains a plantlet which develops as such. A spore is a minute 

 cell containing a nucleus or living germ, the rei^roductive cell germ called 

 by some authors the germinatiug granule. This in turn throws out a 

 highly elongated process consisting of a series of thread-like cells branch- 

 ing longitudinally and laterally, at length bifui'cating and anastomosing 

 the mass, forming the vegetative process known as mycelium or mush- 

 room spawn. 



On this mycelium, at intervals, appear knob-like bodies, called tuber- 

 cles, from which the mushrooms spring and from which they derive their 

 nourishment. See Fig. 5, Plate A. 



Where the conditions have been unfavorable this mycelium has been 

 known to grow for years without bearing fruit. 



Mushroom spores are very variable in size, shape, and color, but are 

 generally constant at maturity in the same genus. Their shape, almost 

 always spherical in the yoang plant, becomes ovate, ellipsoidal, fusiform, 

 reniform, smooth, stellate, sometimes tuberculate, or remains globose. 

 This feature, varying thus with the age of the plant, should be studied 

 in the mature plant. 



MYCELIUM. 



De Leveille has thus defined mycelium : " Filaments at first simple, 

 then more or less complicated, resulting from the vegetation of the spores 

 and serving as roots to the mushroom." 



The mycelium of mushrooms or the mushroom spawn is usually white, 

 but is also found yellow, and even red. It is distinguished by some 

 writers as nematoid, fibrous, hymenoid, scleroid or tuberculous, and 

 malacoid. The nematoid mycelium is the most common. Creeping 

 along on the surface of the earth, penetrating it to a greater or less 

 depth, developing in manure among the debris of leaves or decayed 

 branches, always protected from the light, it presently' consists of very 

 delicate filamentous cells more or less loosely interwoven, divided, anasto- 

 mosing in every direction and often of considerable extent. 



Its presence is sometimes difficult to detect without the use of the 



