232 AGRICULTURAL EXPERIMENT STATION. [Jan. 



fields was very decidedly in favor of the supposition that 

 the trouble in question was a disease of the leaves, due to the 

 organism causing the spots. 



Close inspection of the spots showed tiny black pustules 

 on each ; and these proved to l)e the conceptacles or spore 

 fruits of the fungus, whose development in the leaves causes 

 the death of their tissue in certain regions, and thus pro- 

 duces the spots. The conceptacles appear to belong to that 

 fungus form known as PJiyllosticta Violce Desm. It is one 

 of the so-called " imperfect fungi," whose perfect or winter- 

 spore form and other summer-spore forms have not yet been 

 determined. 



In the fall of 1801 both healthy and diseased plants were 

 received from Mr. Philbrick, and were set in a bench and in 

 a box in the greenhouse. Those which were diseased when 

 sent did not become established so readily as the others, and, 

 although they lived for a time, they eventually succumbed 

 and other diseased plants were set in their places. These 

 met the same fate. Plants with dead or dying foliage were 

 several times removed and carefully examined throughout. 

 In some cases the roots appeared perfectly healthy, but in 

 others there were plainly found the characteristic root galls 

 produced on many plants by a Nematode worm. These 

 were, however, abundant in no instance, and the roots were 

 never sufficiently involved to account for the death of the 

 plant. 



With a thought of the possibility of a complication of the 

 fungous trouble by some other affection, Mr. Philbrick had 

 been asked to watch carefully for any abnormal appearance 

 of the roots, and especially for any root galls, when trans- 

 planting his violets from the held to the greenhouse. He 

 reported that, among three thousand plants, the roots of all but 

 six seemed quite healthy. These six plants were sent to the 

 station, and were found to bear the familiar Nematode galls 

 in small numbers. Four of the affected plants were set in a 

 box and submitted for a month to precisely the same treat- 

 ment. After they had become well established, they were 

 separated into two lots of two each by a heavy tin plate of 

 the full size of the box. The plants of one lot were now 

 watered every few days with about half a pint each of a solu- 



