Notes and Brief Articles 



291 



the affected heads contain dark, hard galls somewhat shorter and 

 thicker than wheat grains. Control measures consist of planting 

 only disease-free seed, practicing crop rotations, and preventing 

 the spread of the nematodes from one field to another by means 

 of infected soil which may cling to the feet of men or animals or 

 to farm implements. 



A recent paper by Stakman and others, in the Journal of Agri- 

 cultural Research, treats of the impossibility of breeding cereals 

 permanently resistant to rust. The facts recorded in the paper, 

 supported by experimental work in the rust nursery and by field 

 observations, indicate that rust resistance is comparable with 

 other permanent characters, and that it is not primarily controlled 

 by seasonal conditions, soil type, geographical location, or other 

 cultural conditions. It is rather an hereditary character, which 

 cannot be produced t>y the accumulation of fluctuating variations 

 within a susceptible line, nor broken down by changes in the host 

 or parasite. The resistance of wheat varieties may vary in dif- 

 ferent regions because of the presence of different biological 

 forms of rust. 



Mr. Frank N. Meyer, one of the most successful agricultural 

 explorers ever employed by our Government, was missed from a 

 steamer on the Yangste River early in June and his body was 

 afterwards recovered. There were no indications as to the cause 

 of death. Many duplicates of Mr. Meyer's collections of fungi 

 in the Orient came to the Garden for determination and were de- 

 posited in the herbarium. Only recently, Mr. Meyer succeeded in 

 discovering the chestnut canker on wild chestnut trees in China, 

 the original home of the disease. 



It is stated by Mr. J. B. Rorer that an alga, Cephaleuros vires- 

 cens, causes a leaf-fall and die-back disease of cacao on practically 

 every estate in Trinidad. This disease has been under observa- 

 tion since 1912 and has been described as attacking any cacao 

 tree at any time during the year, but more readily during the last 



