PAPERS OX BOTANY 223 



ment of the winter wheat, has resulted in a comparative 

 freedom from rust. 



About one-quarter of a mile south-east of the barber- 

 ries, however, was a field of spring wheat with no pro- 

 tection from the infected barberry save distance. A pas- 

 ture abutting upon the hedge extended southward, com- 

 ing close to the wheat. Hordeum jiihatum (squirrel 

 tail) and Agropyron repens in the pasture were severely 

 rusted. Eust had spread first from the hedge to the pas- 

 ture grasses, and then from the hedge and pasture 

 grasses to the spring wheat producing ninety per cent 

 infection. 



Directly across the road, and not seventy feet distant 

 from the infected hedge, was a field of oats in which not a 

 single stalk was free from rust. Grasses along the road 

 and along fences, particularly Dactylis glomerata and 

 Agrostis alha, were heavily rusted. About one and an 

 eighth miles south of the infected hedge was a second 

 field of oats (not shown on the sketch) which was in- 

 fected only to the extent of seventy-five to eighty per 

 cent, this being due partly to the influence of the infected 

 hedge in increasing infection in the fields and grasses 

 near it. The presence of rusted timothy near the orchard 

 indicates also the possible influence of the barberry in 

 spreading the phlei-prafensis fonn of rust. 



Careful microscopic examination was made of oats 

 from the above fields to eliminate the possibility of the 

 rust being Pucciuia coronata. The removal of the hedge 

 in this case has removed an important source of in- 

 fection in tliis neighborhood both for wheat and oats. 

 Further control of the grass-weeds in which the myce- 

 lium of the rust may be perennial should serve as a 

 further means of control. 



The results of our year's work liave served to enhance 

 the significance of barberry eradication as a means of 

 rust control. A large portion of the bushes have been 

 removed from the towns. The countryside remains yet 

 to be done. Information has accumulated to show that 

 the barberry is not only present in great numbers in culti- 

 vation in the country districts, but has escaped from cul- 



