EXERCISE 84 

 LILAC MILDEW A PARASITIC FUNGUS 



Materials. Leaves of lilac infected by the fungus. The fungus 

 is common on lilac leaves in the summer, giving them a whitish, 

 moldy appearance. Leaves should be collected in June, when the 

 powdery appearance is first noted, and again in autumn, when minute 

 black dots may be seen. 



Directions for work. 1. Early summer leaves. Note the loca- 

 tion of the mycelium, where it appears most vigorous, and its 

 relation to the lilac leaf. Use microscope with low power if 

 available, and compare your observations with your study of 

 the relation of molds to the agar or gelatin. 



With the hand lens note the spores, and, if possible, use 

 microscope to discover method of formation of spores, as in 

 your study of blue mold etc. 



2. Examine the leaves collected in the autumn and deter- 

 mine whether the black bodies are related to the fungus. 

 Mount for microscopic examination and crush by pressure on 

 the cover glass. What evidence do you see of spores ? 



References 



BERGEN and CALDWELL. Practical Botany, pp. 229, 230. 

 BERGEN and CALDWELL. Introduction to Botany, pp. 244, 245. 



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