AGARICTTS. 301 



mycelium will permeate the soil, and on the surface 

 there will appear the white-rounded or egg-shaped masses 

 which develop into the "mushroom" themselves, i.e. the 

 spore-producing organs of the plant, the mycelium being 

 the vegetative portion. 



Place some of the mycelium-containing soil in water, to 

 remove as much as possible of the soil from the mycelium, 

 tease out a piece of the latter on a slide, and note that 

 the hyphae branch irregularly, have cross-walls here and 

 there, and are sometimes covered with calcium oxalate 

 crystals, as in the resting mycelium ; look for the rounded 

 growing tips of the hyphae. 



433. Development of Gonidiophore. Pick or wash 

 the soil from a part of the mycelium on which young 

 mushrooms of different sizes are seen ; trace the connection 

 between these and the mycelium, and the stages in their 

 development. Note that 



(1) The young mushroom arises from the mycelium. 



(2) It is at first a rounded or ovoid mass, consisting of 

 uniform solid tissue, as seen on cutting it longitudinally. 



(3) Later it becomes differentiated into a narrower 

 lower portion (stalk) and dilated upper portion (cap). 



(4) Later still, as the cap expands, a ring-like cavity 

 (gill-chamber) is seen running horizontally in the tissue. 



(5) The roof of the chamber is seen to bear numerous 

 white radiating vertical plates (gills), as shown on making 

 horizontal and tangential longitudinal sections. 



(6) Later still, the cap extends further, the tissue 

 forming the floor of the gill-chamber is ruptured, and the 

 gills are now exposed, 



(7) The stalk meanwhile grows in length, carrying up 

 the cap, the gills turn brown, and the place where the 

 rupture occurred is marked by 



(8) The aiinulus, a ring of tissue on the stalk, and by 



(9) A corresponding ragged fringe on the edge of the cap. 



434. " Spore Print." In the fully-grown mushroom 

 note that the gills do not all reach from the edge of the 

 cap to the top of the stalk ; some extend only a part of 



