280 GRASSES OF IOWA. 



Ranunculus. Dr. J. C. Arthur, of Lafayette, Ind., has recently 

 determined that the J'Jcidium Fraxinii has its teuleto sporic stage 

 upon Phi-agmites and that this rust is connected with Fuecinia 

 phragmitis, and that Fucciniaarundinacea occurs upon Fhragmites 

 communis also. 



TJromyces dactylidis occurs upon Poa, Dactylis, Avena and 

 Brachypodium. TJromyces graminicola occurs upon Fanicum 

 virgatum and several other grasses. Uromyces aciiminatus, first 

 described by Arthur, is very common at times on Spartina 

 cynosuroides. It received its specific name from the 'peculiar 

 character of the apex of the spore. 



The prevention of rust. — Various opinions have been expressed 

 in regard to the causes of rust and its prevention. By many 

 agriculturists, for instance, it is thought that rust is depend- 

 ent upon the manner and method of sowing the grain. Some 

 agricultural writers, especially in Germany, have conducted 

 experiments to determine these facts and the statement has 

 been made by some of these writers that where the grain was 

 sown too thick, and soil fertilized, the culms were developed so 

 abundantly that the cereals rust more severely. McAlpine* 

 stated at a conference at Sidney in 1891, that most of the agri- 

 culturists of Victoria found that rusts were most severe where 

 the grain had been thickly seeded. Eriksson and Henningf in 

 their treatment of this question states that it appears to have 

 been but a small factor in the determination of rusr. Another 

 question discussed along this line by these writers is the ques- 

 tion of shallow and deep planting. According to Rostrup wheat 

 sown more than five inches deep is severely affected. The 

 third question discussed 'is that of sowing by the hand as com- 

 pared with sow^ing with a machine. Prom the. results obtained 

 it appears that grain sown by a machine produces a more uni- 

 form stand and it was less rusted than the hand sown. The 

 fourth question is that of sowing a mixture of different cereals. 

 This question was early discussed by Sinclair, As a matter of 

 fact it makes very little difference if the cereals are sown 

 separately or conjointly so far as rusts are concerned. The 

 question of climatic influences is an important one as has been 

 shown by numerous investigators. The question, both from an 

 historical and from an experimental standpoint has been dis- 



*Rust in wheat. Rep. Proc. of the Conference. Sidney. June 'S-S.!' 1891. Agrl. Guz. 

 New South Wales. 2: 7. 1891. 



tOn the diseases of wheat. See Eriksson and Hennlng'. Getrelderoste 300. 



