126 



PROTECTION OF PLANTS — 1923-24 



res. Contrary to the findings of Ducomet ('08), pycnidia were not found in 

 any of the cultures. On Czapek's and cornmeal the sclerotia are more distinct 

 than on potato-dextrose or oatmeal. On the latter two, the sclerotia are massed 

 together and do not appear individually to such an extent. On cornmeal there 

 is sometimes a distance of an eighth of an inch between two sclerotia. On 

 old cultures where a large number of conidiahave been produced, the surface 

 layer will again be covered by a superficial layer of white mycelium, produced 

 no doubt by the germination of the conidia. 



In the case of the Saltation no sclerotia were developed at all. The amethyst 

 color was discernible in all the cultures but the predominating color was 

 yellow. Conidia were produced very luxuriantly in all cultures. On close exami- 

 nation it appeared that each conidiophore always bears a conidium at its tip and 

 others are found lower down. After the first falls others are developed in the 

 same place. 



The results of microscopic examinations of conidia are given in the following 

 table ; 



Spores. 



Org. 



Lenght. 



Width. 



Color in mass. 



Guttulation. 



Que. org. 

 Saltation. 

 V. varians. 

 C tabif. 

 C. 9tram. 

 C. atrov. 



17.8 - 20. 7u 

 17.5 - 19. 7u 



18.0 - 20. 6u 



19.1 - 20. 8u 

 17.5 - 19. 6u 

 16.5 - 18. 8u 



3.0 - 3.7u 

 3.0 - 3.8u 

 3.5 - 3.7u 

 3 - 3.7u 

 b.O — 3.9u 

 0.4 — o.7u 



pink. 



yeUow. 



pink. 



pink. 



pink. 



pink. 



1-3. 

 1-3. 

 1-3. 

 1-3. 

 1-3. 

 1-3. 



The spores vary in size to an appreciable extent. The above measurements 

 are the average of a large number of determinations. In shape they are identical 

 being continuous, cylindrical, slightly pointed at the basal end and rounded at 

 the apical end. Some are slightly curved and restricted at the middle. The 

 number of guttules varies from 1-3. In a few conidia there are 4 guttules but 

 that is an exception. The presence or absence of guttules seems to be governed 

 by the factors of age and nutrition. 



The mycelium is septate in all cases. The cells vary in size to a marked 

 extent. The vegetative cells are cylindrical in shape while the sclerotial cells are 

 more or less rounded to barrel shaped. 



As stated above, sclerotia appeared in all cultures with the exception of 

 the Saltation. They were o^^al to round in shape, black in color, and varied in 

 size from a very minute mass of black mycelium to a well defined body that 

 could easily be distinguished with the naked eye. The term sclerotium is here 

 used to include the small black mass of mycelium with or without setae. 



