226 MAINE AGRICULTURAL EXPERIMENT STATION. I913. 



color of the mycelium may be very different in sets of cultures 

 of the same fungus on different media. A species which on one 

 medium may show much bright red color of the mycelium next 

 to the substratum and extending to the aerial growth may show 

 little or no red color in cultures of the same age on another 

 medium. In this same fungus, other conditions may lead to 

 the production of still other colors: On the other hand there 

 are certain species in which the mycelium remains white what- 

 ever culture medium is used. In regard to color, it is not suf- 

 ficient to state that a form shows a given color without giving 

 some account of the conditions under which this color was 

 produced. In cultures of a given species, the spores may show 

 differences in shape and size. For this reason the measurements 

 of spores as they are usually given in descriptions of species 

 may apply equally as well to the spores of another. Any 

 description of a new species of Fusarium should be based on 

 cultural studies extended enough so that the characteristics 

 which are brought out by growth under different conditions can 

 be taken into consideration. 



There are some media, however, which do not have much 

 value in furnishing characters of growth which can be used in 

 the separation of species of this genus. In these studies con- 

 siderable work was done in comparing the growth of species 

 from different sources on media which contained different 

 amounts of sugars and acids. In general, the conditions which 

 are favorable to the growth of one species seem to be favorable 

 to others. For example, the amount of a given acid which when 

 added to a 2 per cent dextrose broth renders the medium so 

 acid that one of the forms which has been tested will not grow 

 prevents the growth of all. The only exception to this was 

 with the strains F VII, F XV, F XVI, which grew in media 

 which contained enough acid to prevent the growth of other 

 species. The following account gives the cultural characters 

 of a number of forms on different media. 



Germination oe Spores. 



The species isolated from apple were studied in hanging drop 

 preparations of the spores and this taken together with observa- 

 tions of the germination of the spores of other species in agar 



