Sept, i, 1923 
Puccinia glumarum and Hosts for Variety tritici 
399 
Parker (15) interprets purple blotches adjacent to the uredinia as 
evidence of resistance of oats to P. graminis avenae. As indicated in 
Table II and as illustrated in Plate 3, A, dark brown spots often develop 
on certain grass hosts when inoculated with urediniospores of P. 
glumarum tritici. Similar brown discoloration often appears around the 
edge of the uredinia on fairly susceptible grasses such as Bromus sterilis , 
Bromus sitchensis , and others. This type of reaction has been noted 
only on certain species of grasses. Parker (15) also found that the pro¬ 
duction of telia of crown rust on seedlings of oats in the greenhouse was 
an indication of resistance. Although in a few cases telia have developed 
in the greenhouse upon wheat seedlings in connection with the work 
herein reported, this has been interpreted as being due to the effect of 
certain environmental conditions upon the host rather than as a sign 
of resistance. 
SUMMARY 
Field collections of Puccinia glumarum in the western part of the 
United States have been made on wheat, barley, rye, spelt, and emmer, 
as well as on 33 wild grasses. 
It has been shown by artificial inoculation that the rust also will infect 
26 additional grass hosts. This makes a total of 59 species of wild 
grasses which are hosts for this rust as it occurs in the United States. 
The common specialized variety of stripe rust in the United States is 
the one peculiar to wheat, P. glumarum tritici Erikss. and Henn. Field 
observations indicate that the variety developing on barley, P. glumarum 
hordei E. &. H., also occurs in this country. 
The specialized variety from wheat also will infect rye moderately and 
barley slightly. Inoculation experiments have shown that this variety 
also will infect 47 wild grasses. This list includes 19 species of Bromus; 
11 species of Agropyron; 7 species of Hordeum; 7 species of Elymus, and 
one species each of Hystrix, Phalaris, and Sitanion. Stripe rust has been 
collected in the field on twelve additional grass hosts, but it has not yet 
bjeen possible to ascertain if these also are hosts for the specialized 
variety from wheat. 
There has been some evidence that there are several strains of the 
different grass species which react differently to the same variety of the 
rust. There has been some indication also that there are two or more 
strains or specialized forms of P. glumarum tritici. 
Varieties of wheat and wheat allies to' the number of 163 have been 
tested for resistance to stripe rust in a rust nursery at Corvallis, Oreg., 
where an epiphytotic of this rust was produced artificially each year for 
three years. All of these varieties were grown for two years and part of 
them for three years. The results of these experiments are presented in 
tabular form. 
Ninety-two varieties of wheat have been tested for resistance to stripe 
rust in the greenhouse. Some of these were studied three years, some of 
them in two years, and some of them in only one year. The results of 
these experiments are given in tabular form. With few exceptions the 
results of the field and greenhouse studies have agreed quite closely. 
There is a very marked difference in the susceptibility of various wheat 
varieties to stripe rust. More of the common wheat varieties appear to 
be resistant to stripe rust than are resistant to stem rust. When more 
strains of stripe rust are tried this may not continue to be the case. 
Comparatively few of these varieties which were studied became infected 
