536 pETcii : 



appear on hyaline myeelium on the cut surface. Hence tlie 

 macroconidia have been styled the first kmd of spore and the 

 niicroconidia a higher type more adapted to aerial conditions. 



But if the spores are sown in nutrient solutions, or on agar 

 plates, or on blocks of sugar cane, &c., the microconidia 

 invariably appear first. If the substratunx is somewhat dry, 

 the microconidial stage may be of sliort duration, but it is 

 never absent. Hence the microconidiuni must be regarded as 

 the first type of spore. 



Several observers have considered that the macroconidia 

 were produced only within the tissue of the host plant, or 

 beneath the surface of solid or liquid media, "in contrast to the 

 microconidia, which are supposed to be always aerial. This 

 view, however, is not correct. It is true that in hanging 

 drops the majority of the microconidiophores project into the 

 air, while the chains of macroconidia do not ; but this is 

 merely owing to the greater length of the microconidiophore. 

 On decayed tissue, the crop of aerial microconidiophores is 

 always followed by the production of aerial macroconidiophores, 

 and the same occurs also in flask cultures and on agar plates. 

 When the fungus is grown in films of nutrient solution as 

 described on p. 528, most of the conidiophores, both micro and 

 macro, are produced at the edge of the film, but both kinds 

 are also produced within the film. There is therefore no such 

 delimitation as has been supposed. 



One variation from the normal course occurred on agar 

 plates made with a decoction of coconut stem tissue. Two 

 sets of plates were inoculated, the one with hyaline micro- 

 conidia and the other with black spores. Both series grew 

 well, and in three days the plates were covered with a white 

 mass of mycelium bearing microconidiophores. On the fourth 

 day, de Seynes' Stysanus-Yike fructification, which consists 

 entirely of microconidiophores, appeared, and this continued 

 to be produced for the next four days. After the expiration 

 of fourteen days the plates were still white, and there were no 

 macroconidia. In this instance the macroconidial stage was 

 eliminated. As there was no difference between the two 

 series, this eifect cannot be attributed to the type of spore 

 employed in inoculation. 



