128 PRACTICAL BOTANY. 



Examine carefully the way in which the conidia are 

 produced, noting 



a. The sterigmata, peg-like radiating outgrowths 

 from the head of the conidiophore. 



&. The series of conidia, in successive stages of 

 development, which have been successively formed by 

 abstriction from the sterigmata. 



c. The oval form, and spiny surface of the mature 

 conidium. 



In order to observe the successive stages of develop- 

 ment of the conidiophore, small portions of the Fungus 

 should be taken from the white patches, where the 

 growth is younger, and be treated as before. In these 

 specimens the following points are to be observed 



1. The conidiophore as a club-shaped thick erect 

 hypha. 



2. The swelling of the head, though it remains quite 

 smooth. 



3. Minute papillar outgrowths appear on the surface 

 of the head these are the young sterigmata. 



4. The sterigmata elongate, and become attenuated 

 at the tips. 



5. The successive stages of abstriction of the conidia 

 from the apices of the sterigmata. 



III. In order to trace the germination of the conidia, 

 they should be cultivated under microscopic observation 

 on the slide. For this purpose a moist chamber is to be 

 prepared as directed in Part I., p. 16. It will be neces- 

 sary to take certain precautions to reduce the probability 

 of access of foreign spores to a minimum, and so insure 

 as nearly as possible a pure culture. Prepare a nutri- 

 tive solution by boiling French plums in water : this 



