744 



FUNGI 



potassium ammonium phosphate, but the presence of the 

 actively-growing mycelium acts most energetically as a germi- 

 nation stimulus. The reproduction of the fungus from its 

 spores has been successfully carried out by Repin and others 

 in France recently, and their methods for the production of 

 ' virgin spawn ' have already been of great value to the mush- 

 room-growing industry. 



Ex. 310. — Sketch the parts of a full-grown mushroom. 



Pull ofiF the pileus from the stalk and place it with the gills downwards 

 on a sheet of white paper : leave it all night and examine the paper in the 

 morning. The spores fall off and leave a sort of picture of the arrangement 

 of the gills. 



Ex. 311. — Compare the parts of a half-grown 'button' mushroom with 

 those of a full-grown specimen, noting specially the colour of the gills and 

 the form of the annulus and velum partiale in each. 



Ex. 312. — Place small pieces of the pileus and stipe of a mushroom in i per 

 cent, chromic acid for twelve hours ; transfer them first into a mixture of equal 

 parts methylated spirit and water, and then into ordinary strong methylated 

 spirit, leaving them in each solution two hours. 



(a) Cut longitudinal and transverse sections of the stipe, mount in glycerine, 

 and examine under low and high powers ; sketch the form of the hyphse in 

 each. 



[b) Cut sections of the pileus and gills as in Fig. 252. Examine first with 

 a low and then with high powers. Note and sketch the trama, sub-hymenial 

 layer and hymenium of a gill. Observe and sketch the paraphyses and 

 basidia with their sterigmata and basidiospores. 



Ex. 313. — Procure a ' brick ' of ' mushroom spawn ' from a seedsman, break 

 it and note the fine filaments of mycelium penetrating it. Tease out with 

 needles and examine with low and high powers portions of the mycelium 

 in water. Observe and sketch a portion of a hypha with its transverse septa. 



If a mushroom-bed can be examined, observe that the young mushrooms 

 arise from the mycelium in the bed. 



