CLADOSPORIUM 475 



sometimes destroyed by Cladosporium herbarum (Link.). 

 Cugini and Macchiati had previously described a similar 

 disease attacking peas, and attributed it to a new species they 

 called Cladosporium pisi. As this species did not appear to 

 differ from C. herbarum, Lasnier prepared a pure culture of 

 the latter, and infected peas with the spores obtained. The 

 symptoms produced brown blotches sharply defined, and 

 bearing the Cladosporium on the leaves and stem, were 

 identical with those described by Cugini and Macchiati. The 

 diseased plants were small and deformed. 



Lasnier, Bull. Soc. Myc. France, 20, p. 236 (1904). 

 Cugini and Macchiati, Bull. St. Agrar. Modena, 1891, 

 p. 104. 



Orchid leaf stain. A peculiar disease on living leaves of 

 Oncidium crispum, resembling an olive-green stain, is caused 

 by Cladosporium orchidis (Cke. and Mass.). The olive-green 

 sporophores of the fungus emerge in tufts through the 

 stomata, and bear at the apex and laterally the pale olive 

 elliptical spores which become 1 -septate at maturity, and 

 measure about 9-12x3-4 fi. Some spores exceed these 

 measurements, others are smaller. The sporophores spring 

 from a compact mass of hyphae formed in the air-cavity 

 below the stoma. The spores germinate freely in water, but 

 failed to infect the leaves of Cattleya and other genera of 

 orchids. 



Sponging with a solution of permanganate of potash checked 

 the disease. 



Cucumber and tomato black scab {Cladosporium scabies, 

 Cooke) forms dark, depressed spots on cucumber fruit, which 

 gradually extend and form black, convex wart-like structures 

 which often become cracked, exposing the white flesh. These 

 warts vary in size from half an inch to two inches across. 

 When the spores are mature they give a powdery or minutely 

 velvety appearance to the scabs. The same fungus also 

 causes scabbed, black patches on tomato fruit. When the 

 fruit is young when infected it rarely develops normally, and 

 is in most instances stunted and rendered useless. 



Conidiophores rather long and slender, not constricted or 

 nodulose as is usual in Cladosporium. Conidia very variable 

 in size, the smaller ones continuous, the larger ones usually 

 i-septate, very pale in colour, 10-25x8-12 /x. 



