12 



BULLETIN 1162, U. S. DEPARTMENT OF AGRICULTURE. 



at Warren reported that the owners of these hedges had sent him 

 many samples of buckthorn leaves heavily infected with the aecidial 

 stage of crown rust during the spring of 1919. 



Additional observations have been made at Fargo, N. Dak., Antioch 

 and Freeport, 111., and Duluth, Minn., where R. cathartica has caused 

 local epidemics of crown rust. 



RHAMNUS LANCEOLATA, 



Although unknown in the Old World. Rhamnus lance olata Pursh is 

 perhaps the most widely distributed native species. It is commonly 

 known as lance-leaved buckthorn and grows most commonly along^ 

 narrow streams and shaded dry runs. Its ran^e extends from eastern 



Fig. 7.— Plants of Rhamnus cathartica from the hedge shown in figure 5. The great lumps of dirt 

 left on the roots by the stump puller enabled the plants to remain alive. They produced leaves 

 in the spring, and these had abundant secidial infection. Photographed July i, 1921. 



Nebraska and through central Iowa eastward to Pennsylvania and 

 southward to Florida. This shrub has been collected from the 

 following places in Iowa (see fig. 1): Adel, Bellevue, Bloomfield, 

 Centerville. Council Bluffs, Dubuque, Elkader, Indianola, Le Claire, 

 Monmouth, Morning Sun, Mount Pleasant, Osceola, Oskaloosa, 

 Ottumwa, Postville, Salem, Sioux City, Volga. Winterset: also at 

 "The Ledges" in Boone County, in Decatur County, in the north 

 side of Marion County, in Shelby County, and along the South River 

 in Warren County. It is not frequently found adjoining oat fields. 



STUDIES IN IOWA. 



As R. lanceolata is one of the most widely distributed native species 

 it is important to know to what extent it bears the aecidial stage of 



