NOTES AND BRIEF ARTICLES 



[Unsigned notes are by the editor] 



The familiar stem-end rot of pineapples can be largely con- 

 trolled, according to J. Matz, of the Porto Rico Department of 

 Agriculture, by leaving longer stems on the fruit and fumigating 

 with formaldehyde gas. 



Sphaeropsis ulmicola is thought to be the cause of a serious 

 canker of the branches of the American elm in Wisconsin. Most 

 of the trees affected are fifteen years or more old. See Wisconsin 

 Dept. Agric. Bull. 33: 158-163, by E. E. Hubert & C. J. Hum- 

 phrey. 



Mr. H. E. Parks has sent to the herbarium a number of inter- 

 esting, original photographs of California fungi, including good 

 views of Rhizopogon maculatus, Hydnangium carneum, and 

 Secotium tenuipes. 



Plant diseases, especially in greenhouses, have been traced in 

 many instances to the water supply. W. F. Bewley and W. Buddin 

 have cited a number of cases in a recent article in the Annals of 

 Applied Biology. 



A wither-tip of limes, caused by Gloeosporium limetticola, is 

 said to be common on lime trees in British Guiana during July 

 and August, when frequent applications of strong Bordeaux 

 mixture are required to hold the disease in check. Fortunately, 

 the fruits are usually immune after they are half grown. 



Leaf-spot of orchids is not a single, specific disease, but a 

 complication of various troubles needing careful and intensive 

 investigation. This is the conclusion of a number of plant 

 pathologists, including W. B. Brierley, of the new Rothamsted 

 Experiment Station in England. 



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