CKOWN RL'ST OF OATS. 49 



hosts. It is the more coinnioii of the two oat rusts in the United States. 

 So fill- as locality is concerned, there seems to be little diftereuce in its 

 distribution, but comparcil with the stem rust it seems to be especially 

 prevalent in the Atlantic and Southern coast States. Apparently it is 

 not as constant in its occurrence from year to year as the leaf rust of 

 wheat, though the writer is not certain of any instance where it was 

 entirely absent during the entire summer. .Although one of the most 

 Ijrominent rusts in the United States, it is, strange to say, so far as yet 

 known, rather insignificant in most other countries. According to 

 Uarclay (5, Vol. XXX, p. 40), it does not occur on any cereal in India, 

 but a variety, /'. coronaid lihnalayensis, occurs on Byachypodium sylvati- 

 cum. The writer has not been able to find any record of its occurrence 

 in Australia, and although found on European oats, it is apparently not 

 very abundant. 



Wintering of the ureilo. — Although the writer's opinion is that this 

 rust passes the winter in the uredo stage in the warmer latitudes of the 

 United States, there is as yet no good evidence that it does. x\. case 

 where volunteer oats bore this rust in both the uredo and teleuto stages 

 was called to the writer's attention by 3Ir. M. B. Waite, of this Division, 

 the first week of March, 1S94, at Washington, 1). C. The uredospores 

 were found to be in apparently good condition on leaves not yet dead. 

 Uredospores of both crown and stem lusts of oats were observed on 

 volunteer oats at Manhattan, Kans., up to November 2 of the season of 

 1806, but there was no opportunity of determining whether they lived 

 longer. 



LiahiHty of different varieties to this rust. — There is not as much known 

 regarding the liability of varieties of oats to rust as there is relative to 

 liability of varieties of wheat. One reason for this is, probably, that 

 there is less difference in the structure and physiological constitution of 

 the former. In Australia, where the subjectof liability of varieties to rust 

 has received most attention, neither the oat crop nor rust of oats seem 

 to be of much importance. However, the farmers of the United States 

 and of northern Europe know quite Aveli that certain varieties of oats, 

 as well as of wheat, are more exempt from rust than others. In some 

 parts of the country, especially in California, black oats is said to be 

 freer from rust than the white oats, and in the North the White liussian 

 is said to be quite rust resistant. Although this rust is quite abundant 

 in the Southern States,-a certain variety of oats, known most generally, 

 perhaps, as Texas Eust Proof, is universally claimed to be rust resistant, 

 but the writer has had no opportunity of personally determining this 

 matter. When this variety is grown in the North, however, it invari- 

 ably rusts and sometimes badly. As usual, in none of these reports of 

 rust on oats is there any statement as to the species of rust that was 

 present, though a matter of the utmost importance. According to 

 Professor Hays's notes for 1897 on the varieties of oats grown at the 

 Minnesota Experiment Station, Winter Turf, Siberian White, Black 

 21704— No. 10 4 



