132 MORPHOLOGY AND LIFE HISTORY 



2. In thin sections look for absorbing organs (haus- 

 toria) , branching from the mycelium and penetrating 

 through the cell-walls into the cells. 1 Describe 

 their relative length, shape and general appearance. 

 How far do they project into the cells? What do 

 you infer is the function of these organs? Suggest 

 a way in which they might be able to pierce 

 the cell-wall. What other function must they per- 

 form besides the one you have already mentioned? 



3. Where and how does this plant digest its food? 

 What foods does it need? What is their source? 



4. Is there any correlation between the absence of 

 chlorophyll and the habitat of this plant? Explain, 

 and compare with Phy corny ces and Marchantia. 



5. Make a drawing showing three cells of the host, 

 with the adjacent mycelium and the penetrating 

 haustoria. 



F. Asexual Reproduction: 



1. Observe the chains of spores (conidia, or conidio- 

 spores). On what are they borne? Describe their 

 shape, color, size. Are they all of the same size? 

 Which is the youngest conidium in a chain? Why 

 do you think so ? Of how many cells is each conidium 

 composed? Are they attached to each other? If 

 so, how? 



2. Observe the conidia-bearing hyphae (conidiophores). 

 Describe their shape, and the appearance of their 

 contents. Do they have cross- walls? Observe 

 this last point carefully, and describe. 



3. Describe in detail, from your own observations, 

 the method of formation of the conidia. 



1 The haustoria are difficult to identify, especially with poor sections 

 and too much time should not be spent in trying to detect them. 



