THE FUNGI. 



3. Place some fresh leaves, bearing Cystopus, in. a warm, 

 moist chamber over night. In the morning mount some of 

 the white growth in water. After an hour or so examine 

 for motile zoospores which have escaped from the spores. 

 After watching their motion for a time, run iodine solu- 

 tion under the cover glass and determine whether or not 

 the motion is produced by cilia. Draw. The zoospores 

 remain motile only a short time. They then grow by cell 

 division and produce new plants of Cystopus. 



4. Under the cover of a preparation similar to that in 

 Number 2 run Schultze's solution. Is the cell wall com- 

 posed of ordinary or of fungous cellulose? 



5. Macerate in caustic potash for some time small pieces 

 of the leaf bearing the Cystopus, taking care to put in as 

 little as possible of the healthy parts of the leaf. Then 

 tease out the Cystopus in a drop of water on a glass slip, 

 add a drop of Schultze's solution, cover and examine. 

 Find tangled masses of the mycelium which have been torn 

 out of their positions in the cells of the host plant. Do 

 you find septa? Draw a portion of the mycelium, show- 

 ing the hyphaB and the chains of asexual spores in position 

 on the hyphse. 



6. Place a leaf bearing sori between two pieces of pith 

 and cut delicate transverse sections through the sori, 

 keeping the pith and razor wet with alcohol. Examine 

 some of the sections, applying Schultze's solution. If the 

 sorus was young, the gonidiophores (stalks bearing the 

 asexual spores) will be found just below the epidermis of 

 the host. If the sorus was old, the epidermis of the host 

 will have broken away and its edges will be turned out. 

 Look for haustoria, the minute transparent globular 

 suckers which the Cystopus sends into the cells of the 

 host to rob them of their contents. These will be most 

 easily found in the youngest sori. Draw several, showing 

 their attachment to the mycelium. If they cannot be 



