298 THE BIOLOGY OF THE PLANT 



into one another ? Do these different shades have 

 any definite relation to the centres of the masses 

 of mould ? How high above the surface does the 

 mould rise ? Can you with a lens distinguish the 

 individual stalks or aerial hyphae, each with a 

 tuft-like head, the conidiophore ? Examine with 

 a lens and note the root-like threads forming the 

 mycelium, which runs over the surface of the 

 substratum. With the fine forceps pick up a 

 small mass of mould. Is it attached to the sub- 

 stratum or is it merely lying on the surface ? 



Tap a piece of mouldy bread and notice the 

 cloud of dust, the spores, given off. 



Microscopic Characters. 



a. The mycelium. — With the fine forceps place some 

 of the m\'celium on the slide in a drop of water, 

 twenty per cent, glycerine or thirty per cent, alco- 

 hol. Does water readily wet the mould? Using fine 

 dissecting-needles, gently pick to pieces the mass 

 of mould, and examine under both the low and 

 the high powers. What is the structure of the 

 mycelium ? Do the threads, the mycelial h.y- 

 phae, branch ? If so, are the branches given off 

 at definite points? Do the hyphae consist of a sin- 

 gle cell or of several cells ? Do the hyphae vary in 

 diameter ? What is their shape at the end ? What 

 is the structure of the cell- wall? What do the 

 hyph^ contain ? Examine mycelium of the dif- 

 ferent colors. What variations in structure and 

 state of development do you find ? 

 Make several drawings to illustrate the various ar- 

 rangement of the mycelial hyphae and their structure. 



h. The aerial hyphse. — At what points do the aerial 



