LABORATORY AND FIELD WORK 405 



8. Soak a cedar apple in water for a few minutes, then place 

 it on moist filter paper or blotting paper and cover it' with a tumbler. 

 Examine it after a few hours ; note the finger-like projections that 

 it has pushed out. Mount a small bit of one of these projections 

 in water and study it under a microscope. It will be found to 

 contain spores. Which kind of spores of the wheat rust do those 

 in the cedar apple resemble ? 



9. Compare the cluster cups of the rust on the apple (or of the 

 very similar rusts on the crab-apple or hawthorn) with those of the 

 rust on the barberry. What differences do you find? 



CHAPTER VIII 



It is not necessary, though preferable, to study in the laboratory the 

 same species of mushroom that is described in the text. Mushrooms 

 of various kinds may be gathered at any time during the summer or 

 fall, and are readily preserved in 70 per cent alcohol. Be certain 

 to obtain portions of the vegetative threads. Fresh horse- or cow- 

 dung, placed in a battery jar and covered, will produce a good crop 

 of mushrooms for class study in from ten to fourteen days. Mush- 

 room spawn, readily obtained from dealers, may be' planted and will 

 give abundant material for study, if the necessary conditions for its 

 cultivation are at hand. Directions for planting and for the care of 

 a mushroom bed are given with the spawn purchased. Atkinson's 

 Mushrooms, Edible, Poisonous, etc. has an interesting chapter on the 

 cultivation of mushrooms. 



1. Examine material that shows various stages in the develop- 

 ment of fruiting bodies. Notice the thread-like underground 

 vegetative portions of the plant. Find also swellings ("buttons") 

 of different sizes. 



2. Cut one of the larger buttons in half from top to bottom ; 

 what structures do you find inside ? 



3. Study the way in which the buttons develop into fruiting 

 bodies. By means of sections made as above described, follow 

 the development of stalk, cap, and gills. Sketch sections showing 

 two stages in development. 



4. Study a full-grown fruiting body. Notice : 



a. The shape, size, and color of the cap. Does it bear scales ? What 

 is the color of the flesh when it is freshly broken ? Does the 

 color change after it is broken ? 



