52 



CEREAL RUSTS OF THE UNITED STATES. 



Tablk 7. — I'redo coronata on rarietles of oats — Ci>iitiinied. 



Localities autl names of 

 varieties. 



|Subspe- 

 cies. 



Per cint of rust i- 

 ness at — 



Garrett ' Salina, 



Park, June 30, 



July 16. 1895, 1896 



Average. 



Kemarks. 



France : 



Belgian Black Winter 



Black Hungarian s 



DEtanipes p 



Grey Houdan p 



Grey "Winter p 



Jaune de Flandre p 



Joanet*e p 



Noire de Brie p 



Rousse Couronnee p 



"White Hungarian s 



Siberia : 



Siberian (Nerchinsk) 



Siberian No. 7 



Spain : 



Civada Blanca Grjuija de p 

 Barcelona. 



Portugal : 



Abrantes p 





A black chart" sort. 



The Flemish oat. 

 Short straw. 



* Not planted in 1895. 

 Do. 



Tliere was little difference in the amount of rust on different varieties 

 during the second season, all being very badly affected. As the black 

 stem rust also was present, it was very diflScult to grade, even approxi- 

 mately, the amount of crown rust alone. It is believed that had the 

 varieties been sown quite early in the case of the experiment at Gar- 

 rett Park many of them would have escaped entirely, as the rust did 

 not appear until very near harvest time, and only four varieties were 

 rusted as much as 40 per cent. On the whole, the two years' experi- 

 ments do not show much difference in the comparative liability of 

 varieties of oats to the crown rust. 



Damage. — The writer knows of no instance where it could be proved 

 that this rust cau.sed any really serious damage to oats, under ordinary 

 conditions, when the black stem rust was not also present; but never- 

 theless it is quite possible that it may occasionally cause considerable 

 injury. In any event it seems to be of more economic importance in 

 this than in most other countries. 



BLACK STEM RUST OF WHEAT. 



[Puccinia grammis tritivi Eriks. and Henu.). 



Pnccinia granipiis has always served as a convenient species in which 

 to include such grass rusts as show no particular morphological indi- 

 viduality, but which resemble this species, and as a result it is credited 

 with more host plants than any other rust. The writer has found at 

 least 38 different grasses given as hosts for this rust in America, and 

 Eriksson states (31, p. 119) that lO.j are recorded in the herbarium of 

 the division of plant physiology of the experiment station at Stock- 

 holm as hosts for this species in Sweden. Xearly all such identifica- 

 tions are of little value from an economic standpoint, many of them 

 are wrong morphologically, and some of them are little better than 

 guesswork. Errors in identification often arise from the fact that the 

 specimens show but one stage of the rust, usually the uredo stage. 



