336 BULLETIN No. 189 [June, 



colored, slightly wrinkled epidermis. An examination of the underlying tissues 

 revealed the same general color and numerous, somewhat darkened filaments pene- 

 trating the cells in all directions." 



Wollenweber 1 42 in 1913 described a species, RJiizoctonia poto- 

 macensis Wr., which causes a fruit rot of green tomatoes. He stated 

 that this species differs from Rhizoctonia Solani in the character of 

 its attacks, in that concentric, subepidermal mycelial zones are formed 

 within the tomatoes. 



VIOLET, Vioki odorata 



During the fall of 1913 a number of violet plants in the floricul- 

 tural greenhouses were found to be diseased. A few had stem rot, 

 while on others only the bases of the petioles were somewhat rotted. 

 "Where the pots were set close together and the plants overlapped, the 

 brown strands of R. Solani could be plainly seen spreading out from 

 one plant to another. However, in no case was the disease severe ; it 

 is probable that the fungus was living saprophytically on the lower 

 leaves. 



Duggar and Stewart 32 observed, in a greenhouse in New York, one 

 case of destructive violet stem rot due to Rhizoctonia and a second 

 case similar to the attack described above. 



ADDITIONAL OBSERVATIONS 



Beside the hosts that have been mentioned, observations have been 

 made in the floricultural greenhouses of diseased seedlings and cut- 

 tings of a number of other plants, tho no work has been done further 

 than to make a microscopic examination of the diseased material. 



Below is a list of seedlings and cuttings found damping off in the 

 spring and fall of 1914, with the percentage of loss resulting. In all 

 cases Rhizoctonia proved to be the cause of the trouble. 



Percentage 



Seedlings Damping off, April 6, 1914 of loss 



Amaranthus caudatus 75 



salicifolius 90 



Bartonia aurea 90 



Calendula Pongei 1-2 



Celosia Huttoni, var. Thompsonii magnified 75 



Chrysanthemum hortorum 30-40 



Dianthus chinensis 80 



Heddewigii 30 



' ' latifolius 80 



Godetia sp 80 



Gypsophila muralis 30 



Kochia trichophylla 99 



Lavatera arborea variegata 5 



Linaria Maroccana 5 



Linum grandiflorum rubrum. 30 



Lychnis coeli rosa 90 



Portulaca oleracea 80 



Schizanthus sp 2-4 



