AGARICUS CAMPESTRIS 143 



If so, describe their arrangement within the 



pileus. Do they extend into the gills? 

 4. Make a diagram, life size, to illustrate the relation 



to each other of the hyphae of the mycelium, stipe, 



annulus, pileus, and gills. 

 Reproduction: 



1. Mount (in clearing fluid or water) thin cross-sec- 

 tions of a gill. 



2. Observe the differentiation of the gill into a central 

 tissue or trama, an outer, spore-bearing tissue, or 

 hymenial layer (hymenium), and, between these 

 two, a sub-hymenial layer. Of what are these 

 tissues composed? How are they distinguished 

 from each other? Show by diagram the position 

 of these three layers. 



3. The hymenium. Using a prepared slide, state the 

 direction of its cells relative to the surface of the 

 gill. Distinguish in it two kinds of cells, (a) club- 

 shaped ones, paraphyses; (b) basidia (sing., basid- 

 ium), bearing sterigmata (sing., sterigma). How 

 many sterigmata terminate each basidium? Ob- 

 serve the spores, borne on the basidia and hence 

 called basidiospores. Are the basidiospores all of 

 the same size? Explain. Describe their color, 

 shape, surface markings (if any), and the number of 

 cells of which they are composed. Is the color of 

 the spores constant? To what is the color of the 

 gills due? 



4. If a pileus with the stipe removed is placed with 

 the gills down over a clean, smooth piece of paper 

 (black or white according to the species used), then 

 covered with a tumbler or other suitable glass 

 dish, and left over night, a print of the spores, as 

 they fell from the gills, will be found on the paper 



