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6 RESEARCHES ON FUNGI 



I examined the surface of the soil carefully and discovered, to 

 my surprise, that, within one or two feet of the stump, it was 

 partially covered with red mycelium of Psathyrella disseminata. 

 Reddish tufts of mycelium, like those in Fig. 21, B, a and D, a, 

 looked upwards from the ground. I left the soil undisturbed. 

 After some days had passed, there came a heavy rain-shower 

 which thoroughly soaked the earth. The red mycelium at once 

 revived and, about four days later, gave rise to an abundance 

 of fruit-bodies gregariously crowded in the manner shown in 



Fig. 20. 



The whole chain of events leading to this sudden and simul- 

 taneous production of thousands of fruit-bodies was doubtless as 

 follows. The mycelium vegetated in the stump and, in moist 

 weather, grew outwards from the stump for from one to two feet 

 through the superficial layer of the soil. Within the soil, it de- 

 veloped into an anastomosing network of fine red cords and hyphae 

 and, when thus developing, to some extent invaded the soil's 

 exposed surface. The whole of the mycelium within and above the 

 soil became laden with a certain amount of reserve food materials 

 derived from the hyphae vegetating in the stump. Then came a 

 spell of fine warm weather, in consequence of which the mycelium 

 dried and became inactive. Then came a heavy down-pour of rain. 

 The mycelium at once revived and, at the expense of its reserve 

 food materials, within four days, produced a crop of fruit-bodies at 

 the surface of the soil. 



The Structure and Functions of an Ozonium. — The tough red 

 mycelial network of hair-like cords and isolated hyphae which has 

 just been described may be called an ozonium, for this name was 

 originally given to mycelial systems of this character at a time when 

 their connection with the fruit-bodies of various fungi had not yet 

 been traced. An ozonium is now known to be produced by a 

 number of Hymenomycetes. The commonest, which is reddish like 

 that of Psathyrella disseminata, belongs to Coprinus domesticus and 

 is frequently found beneath and upon the loosened bark of fallen 

 Elm-trees. 



An ozonium, such as that of Psathyrella disseminata or Coprinus 

 domesticus, is not to be confused with the ordinary vegetative 



