58 



Mycologia 



The disease has been found on several varieties of tomatoes. The 

 actual damage to this new host is slight, but the fungus is kept 

 alive and spread to new fields by this means. 



The Tropical Research Laboratory of the United Fruit Com- 

 pany, which was formerly located at Zent, Costa Rica, and closed 

 during the period of the war, is being reopened at Changuinola, 

 Panama. Dr. John R. Johnston, professor of plant pathology 

 in the University of Havana, has been appointed director of 

 tropical research for the company with headquarters in Havana, 

 and two pathologists will be located at the Laboratory in Panama, 

 one to continue work on the banana disease, and the other to work 

 on the diseases of the coconut, cacao, and other crops. 



Referring to Puccinia 'strum arcticum (Lagh.) Tranz. the state- 

 ment has recently been made that " Outside of Alaska only two 

 American collections are known." (Bull. Torr. Bot. Club 47: 

 468) [Oct., 1920]. This statement needs amplifying. There are 

 in the herbarium of the University of Wisconsin specimens repre- 

 senting 30 collections from upwards of 20 localities in Wisconsin 

 ranging from the north to within about 40 miles of the southern 

 boundary. All of these are on Rubus triflorus (R. pub esc ens) 

 and all of the specimens on this species of Rubus are of the 

 arcticum type while all of those on Rubus strigosus are of the 

 americanum type. This raised a query as to whether the cause 

 of the difference lay in the parasites or in the hosts. 



J. J. Davis 



" Collar-rot of Apple Trees in the Yakima Valley," by J. W. 

 Hotson, is an important contribution to this subject published in 

 Phytopathology for November, 1920. The author believes that 

 the only essential condition of collar-rot is a permanent wound 

 of the bark at the collar of the tree; which may be caused by 

 Bacillus amylovorus, Armillaria mellea, Polystictus versicolor, 

 gophers, frost, plowing, gradual corrosion by oxidation, etc. 

 Where the injury is severe, the tree should be removed; in other 



