102 LABORATORY AM) FIKLI) KXKllCISKS 



LILAC MILDEW (MICROSPHAERA ALX/) 



1. Structure. Observe the upper surface of leaves infected 



with the parasite and note 



a. The white mycelium covering the leaf surface with a 

 whitish mass of hyphse. Is this the plant body of 

 the fungus ? How is it anchored to the leaf and how 

 nourished ? "What is the structure of the body of 

 the plant? 



2. Reproduction by ascocarps, or fruits. These are dark 



bodies scattered over the surface of the leaf. 



a. Distribution of the ascocarps. Outline a portion of a 



leaf surface, showing the distribution of the mycelium 

 and the ascocarp fruits on a leaf. 



b. Structure of ascocarps and asci. Remove ascocarps to a 



slide in a drop of alcohol and glycerin by scraping 

 them from a leaf with a needle. Avoid scraping off 

 dirt and portions of the leaf. Note with low power 



(1) The dark wall and app<'n<l<i</<'x. The structure of the 



wall can be ascertained by slight crushing. Note 

 its cellular structure if it is not too dark. Note 

 the shape and attachment of the appendages to 

 the wall of the fruit. Draw a fruit body and one 

 or two appendages. 



(2) Asci and ascospores. These are obtained by crush- 



ing ascocarps under a cover glass with a needle. 

 How do asci and spores get out of the fruits in 

 nature ? When will spores be liberated and dis- 

 seminated ? How disseminated ? 



(3) Spores. Note their shape and the number in each 



ascus. . 



3. Drawings. Draw a fruit body from which asci are being 



pressed out. Draw an ascus and spores. 



