IOWA ACADEMY OP SCIENCE 
59 
e. g., P. graminis secals on rye, P. graminis tritici on wheat, P. graminis on 
Poa. 
Klehahn®® too has found that some of our rusts must be considered as biologic 
forms. Demonstrated especially in connection with the aecidial forms of the 
grass and grain rusts. 
Carleton™ arrived at somewhat similar conclusions. 
Arthur'^^ also reports on the restrictive development of some of the species. 
Freeman’s^'' work clearly indicates as quoted by Reed that the uredospores of 
barley will infect wheat and rye as well as barley and oats. The uredospores 
from rye will infect rye, wheat, barley, but not oats. 
The following record is a summary of the work conducted by this Station 
since 1892, and the previous work by Dr. Halsted and Dr. Bessey. We have 
therefore a record of the abundance of fungus diseases in Iowa for nearly 
twenty-five years. The earlier records, of course, are not so complete as the 
later records. For use of characters see end of table. 
Eriksson and Henning Die Getriederoste. Stockholm. 1896. 
®®Die wirtswechselnden Rostpilze. Berlin. 1904. 
. '^oCereal Rusts of the U. S. Bull. Bur. PI. Ind. Veg. Phys. and Path. U. S. Dept. 
Agrl. 16. 
■^^Cultures of Uredineae 1904. Jour. Myc. 11 : 50 . 
72Cited by Reed 66. 
