

242 ANNALS OF THE MISSOURI BOTANICAL GARDEN 



[Vol. 10 



weight increase when this reagent was added to the medium. 

 It is one of the commonest of the citrus fruit-rotting fungi on the 

 market and can be easily distinguished by the olive-green color 

 and large size of the spores. 



Aspergillus sp. — This fungus was reported by Dr. Fawcett as 

 rotting fruit at 27°, 30°, and 34° C. In spore size and the structure 

 of the spore-bearing heads it corresponds with A. niger, but the 

 spores in mass appeared first cinnamon-brown and then dark 

 brown, and rarely if ever were dark enough to be considered black. 

 It grew readily in most media, using the ordinary inorganic 

 nitrogen sources. It also produced acid under certain conditions 

 but apparently not so abundantly as the true A. niger. It may be 

 a strain of A. niger or of a closely related species. 



Diplodia nataletisis Evans. — Cultures of this fungus were also 

 furnished by Dr. Fawcett. The fungus grew well on most of the 

 common synthetic media, forming a black, carbonaceous mat of 

 close texture, but it did not form pycnidia readily. After growth 

 the culture solution was dark colored, a deep red as the fungus 

 matured, but if citric acid salts had been added this color was 

 lessened. This fungus was originally reported from South Africa, 

 where it caused a black rot of citrus fruits, and Fawcett ('15) 

 later reported the fungus from Cuba, on grapefruit. 



Alternaria Citri Pierce. — This fungus was also furnished by 

 Dr. Fawcett. It was a slow-grower on most media, taking more 

 than 20 days to come to a maximum growth. It produced spores 

 very sparsely and did not grow at a high acidity. This fungus 

 was originally described by Pierce ('02) as the cause of black 

 rot of navel oranges, but the description was short and the inoc- 

 ulation data incomplete. Later, Patterson, Charles, and Veih- 

 meyer ( '10) reported a Stemphylium isolated from oranges affected 

 with black rot. No further work has been reported in connection 

 with the pathogenicity of this organism. This fungus will be 

 contrasted with the next one mentioned; in regard to cultural 

 characters. 



Alternaria sp.— On the local market I found lemons apparently 

 rotting with a typical brown rot, but in attempting to isolate 

 Pythiacyslis from these an Alternaria was frequently found. Vari- 

 ous cultures of this organism were obtained and compared with 



