59 



3rd. What is the parasitic action of the fungus in favourable 

 circumstances. 



In the first experiment Dr. Lopriore found that young wheat 

 plants artificially infected with Cladosporium spores obtained from 

 the shotted chaff of wheat, and put with the fungus in some drops 

 of sterilized water upon their blades, were much checked in 

 growth, and only attained to a height of from 20 to 24 inches, 

 and produced but few grains, which, however, showed no traces 

 of fungus infection. 



In the second experiment, wheat grains free from the attack of 

 the fungus, and some that were attacked by it, were sown in 

 two flower pots filled with earth the affected grains in the 

 middle of the pots, those unaffected near the edges. The result 

 was, that the foots of the sound grains were penetrated by 

 mycelial filaments. The stems showed no traces of infection, but 

 the ears and grains at ripening time were seriously affected by 

 the fungus. 



For the third experiment, wheat grains with the fungus 

 upon them were sown in two flower-pots filled with earth, which 

 were put in a hot-house in a light situation. The fungus in 

 the warmth and dampness of the surroundings soon destroyed 

 these plants. The further investigations as to the course of the 

 fungus showed that it either attacked the wheat plants in a 

 young state, so as to quickly destroy them, and to develop 

 itself abundantly in the lower part of the stem in the usual 

 form of conidia; or it attacked the plants in other and less 

 serious ways, and finally reached the ears without breaking 

 through the framework of the plant. Dr. Lopriore's conclusion 

 is that all the pathological circumstances, from the germination 

 to the full ripening of the ears, indicate that the fungus has a 

 very clear and defined progress in its host plant, and that there 

 can hardly be a question as to accidental infection. The power 

 of the spores to propagate from year to year, and the formation of 

 sclerotia, and of chlamydospores in the stalk, solve the question 

 of the destructive nature of the fungus, and show that it is able, 

 by many modes, to maintain itself and to spread. 



Dr. Lopriore warns cultivators against sowing corn infected 

 by Cladosporium herba/ru/m, and to take care to steep the seed, 

 and to be careful concerning changes of seed. In Sweden, 

 barley is steeped in weak sulphuric acid, a solution of from 

 1 to 1| per cent, Dr. Loptiore adds that there is no doubt that 

 steeping seed corn in this solution does destroy the spores of the 

 fungus. 



Mr. Worthington Smith, who has furnished the admirable 

 illustrations of Cladosporium herbarum for this report, states 

 that the mycelium of this fungus will do well in the ground, and 

 that he has seen it growing on and in the ground often, also 

 growing on wood, and even on painted wood, and this being the 

 case it is reasonable enough to believe that the Cladosporium 

 would grow with the corn from sowing time until harvest. 



