PTMTGOUS DISEASES OF THE VIOLET. 341 



frequently met with, particularly upon specimens re- 

 ceived from Massachusetts. The differences between 

 this and the Phyllosticta are chiefly microscopic. The 

 spores, for example, instead of consisting of one cavity, 

 have a cross partition dividing them in two near the 

 middle. The spore-bearing vessels (pycnidia) are pale 

 pink colored and the hole upon the free side has a dark 

 border. The diseased portion is a less well-defined spot 

 than in previous cases, and is more like a brown patch. 



VIOLET ANTHKACNOSE {Glceosporium ViolcB, B. & M.). 

 A genuine anthracnose is met with upon the violet. 

 This does not produce a spot, but the side of the leaf 

 may be attacked and become brown and shrivelled, the 

 trouble spreading over the whole leaf in the worst cases. 

 When viewed under the microscope the surface of the 

 diseased portion shows many patches where the spores 

 are borne upon the surface. The fungus, after running 

 in aU directions through the tissue of the leaf, concen- 

 trates at certain points and there rupturing the skin 

 produces large numbers of small spores upon the exposed 

 surface. 



A SECOJTD FORM OF ANTHRACNOSE {Colletotrichum). 



Closely related to the last is a second species of 

 anthracnose that belongs to the genus Colletotrichum. 

 This causes a deadening of irregular patches in the leaf, 

 and, owing to the numerous dark, stiff hairs, the affected 

 parts may appear almost black. 



There is a bacterial disease that causes the central 

 portion (crown) of the plant to decay, and ruin is quickly 

 effected. It frequently works in connection with the 

 other fungous diseases and no satisfactory treatment is 

 suggested for it. 



But few satisfactory results have been obtained by 

 treating the violets for fungous diseases. Several 

 growers have been faithful in applying the ammoniacal 



