266 



BULLETIN 94. 



During the winter of 1894-5, some bean plants in the horticul- 

 tural forcing houses of Cornell University were affected by this 

 disease and quite a number of them presented brown and quite 

 deep ulcers on the stems of the surface of the ground. A few of 

 the*plants went so far as not to be able to stand. Some of the 

 worst ones were pulled up, but others which 

 were quite badly diseased remained in the bed 

 and all gradually recovered completely. The 

 plants were six to ten inches in height when the 

 trouble was called to my attention. When the 

 plants attain this size the disease cannot make 

 such headway, but even very young plants will 

 frequently recover from the effects. 



It is more serious when it attacks smaller seed- 

 lings, as radishes, lettuce, etc. Egg plants and 

 cabbages as well as others are known to be affected 

 Both the plants in seed beds in the forcing houses 

 have been quite seriously affected by this fungus. 

 Lettuce is frequently eaten off at the surface 

 of the ground and the plants supported by others 

 near may remain erect and fresh for several 

 days. Gradually, however, if not quickly, they wither and fall 

 when the fungus grows in the tissues farther as a saprophyte. If 

 such plants be placed in a moist chamber, it is not necessary to 

 place them in water, in a day or two there will be developed on 

 the surrounding moist paper on which it is well to place the plants, 

 a profuse growth of mycelium composed of whitish threads. To 

 be sure that these threads are those of this fungus and not those 

 of some mucor it will be necessary to have recourse to the micro- 

 scope. The most characteristic peculiarity of the threads of the 

 mycelium is to be found in connection with the branching. The 

 freshly developed threads branch freely but not profusely, they 

 are colorless, composed of elongated cells 9 P-II i>- in diameter and 

 IOO/J--200/'- in length. The protoplasm is finely granular and 

 contains numerous small rounded vacuoles. The branches extend 

 to an angle usually of between 30 and 60 degrees from the main 

 hypha and very near the point of attachment are a little curved 

 toward the point of growth of the same. At the point of attach- 

 ment with the parent hypha the branch is considerably smaller 



55- Sterile fungus 

 grown on slide 

 from seedling of 

 Centaurea candi- 

 dissinia. 



