98 PRACTICAL BOTANY. 



here and there single hyphse diverge from the rest, and 

 ramify through the compost. 



II. In order to obtain an actively growing mycelium, 

 bearing " mushrooms," the brick is to be broken into 

 pieces, and these must be buried a few inches deep in a 

 compost of similar nature to that of the bricks : the 

 whole is to be kept moist, at a moderately high 

 temperature, and in the dark : the stoke-hole of a con- 

 servatory is well adapted for the cultivation of mush- 

 rooms. After a peiiod of a few weeks, the compost 

 will be found to be permeated by a mycelium, similar 

 to that in the brick of " spawn," while numerous 

 mushrooms of various size will be found connected 

 with it : such a culture as this will suffice for the study 

 of Agaricus campestris in the laboratory. 



III. Remove a small piece of the mycelium of an 

 actively growing culture, mount it in water, and observe 

 under a low power that it is similar in its main 

 characteristics to that in the dormant state in the 

 brick of spawn. 



Having teased it out carefully with needles, examine 

 it in detail under a high power, and observe 



1. The hyphae, of cylindrical form, and with rounded 

 free ends. 



2. The irregular branching of the hyphae. 



3. The septa, which are transverse, and situated at 

 irregular intervals. 



4. HyphaB may frequently be seen to be incrusted by 

 numerous rod-like crystals : these are especially 

 numerous in the dormant mycelium : it is to this, in 

 great measure, that the mycelium owes its chalky white 

 appearance. 



