204 Report of the Botanist of the 



in one of the Station vineyards for six seasons. Although but 

 few of these plants had been gro\vn thriftily, none of them had 

 shown pronounced symptoms of disease. Aecordingly, we were 

 surprised to find the roots of many of them covered with the same 

 fimgris which had been found on the diseased gooseberries at Marl- 

 boro. The fact that it occurred on apparently healthy plants 

 caused us to doubt the correctness of our former conclusions. 



Pieces of the fungiis-infested roots were stuck in moist steril- 

 ized sand in a Mason fruit jar previously made sterile by a solu- 

 tion of corrosive sublimate. In about six weeks they began to 

 show conidial fructification like that of Dematophora. 



From diseased grape roots placed in the Mason jar sand cul- 

 tures we had previously obtained the conidial fructification of a 

 Dematophora. (See Grape Root Rot.) The rhizomorplis of the 

 gooseberry fungus were strikingly like those of the grape Dema- 

 tophora except that the hyphse composing them were slightly 

 smaller. Accordingly, we expected to get the same sort of 

 conidial fructification; but the spores of the gooseberry fungus 

 were larger and the branching of the sporophores different. 

 We believe the gooseberry fungus to be a species of Dematophora, 

 but there is some doubt about it being an active parasite. 



During the past season the gooseberry disease at Marlboro 

 spread but little owing probably to the dry season. In the wet 

 season of 1898 it made rapid progress. The owner of the dis- 

 eased gooseberries believes that the plants have died through some 

 evil influence of a large black walnut tree^^ which stands at the 

 comer of the plantation where the disease started ; but it is scarcely 

 possible that this can have been the direct cause. 



dwarfed foliage. 



In another gooseberry plantation we saw a few plants which 

 appeared healthy, except that all of the leaves were abnormally 



23 For another case of supposed injury by black walnut tree, see Grape Root 

 Eot on pages 297-298. 



