GRASSES OF IOWA. 263 



fungi belonging to the Uredineae as will be made clear in the 

 following pages. The Uredineae are among the most destruc- 

 tive of the parasite fungi of cultivated and wild plants. Well- 

 known illustrations are, cereal rusts, rust of apple, coffee leaf 

 disease, hollyhock rust and carnation rust. The rusts are 

 common on a large number of grasses. The most imporlant of 

 those affecting Iowa forage plants will be taken up under the 

 head of (1) rusts of cereals, (2) rusts of other grasses. 



History — Rust was well known to the ancients. This affec- 

 tion is mentioned in connection with smut. It is referred to in 

 several places in the Bible.* Aristotle mentions its occurrence 

 and causes. Plinius, Columella, Ovidius and other writers 

 mention the occurrence of rust. Bub little mention was made 

 of it during the middle ages, though beginning with the seven- 

 teenth century reference to it became frequent. Some of the 

 laws looking toward the extermination of the barberry date 

 from 1660 when an act having that object in view was passed 

 in Rouen. In 1755 Massachusetts passed a law lookicg towards 

 the extermination of the barberry. A complete and full history 

 will be found in ihe work of Erikssoa and Henning. 



RUSTS OF CEREALS. 



The subject of rusts is one of special interest to us because 

 large losses are usually entailed by our cereal crops. During 

 the last decade several wheat crop failures in parts of our state 

 have been caused by rust. It is, therefore, proper that this 

 subject should receive consideration. 



Eriksson and Henning, + in their recent monograph, find that 

 our cereals have several special] zed forms of rusts. Carleton,+ 

 as the result of some careful studies, finds that our cereal rusts 

 are specialized. 



*5 Moses 28: 32. 1 King 8: 37. 2Chro. 6:28. 



tDle Getreideroste ihre ?eschichte und natur sowie Massregeln gegen dleselben. 

 Stockholm. 464. pL 13. map I. f. .5. 1896. 



tCereal Rusts of the United States. Bull. Div. Vegetable Phys. and Path. U. S. Dept. 

 Agrl. 16. 



