712 
Journal of Agricultural Research 
Vol. XXVIII, No. 7 
tion of the plants shows that they differ only in minute morphological details. 
They are all of the White Tartar (White Russian) type. The data on these, from 
Table I, are given separately in Table III. 
The seed of the variety called Eclipse was mixed and produced, in addition to 
the resistant plants, others which were markedly susceptible. 
Table II .—Data on varieties of Avert a- saliva resistant to oat stem rust 
Host 
Lot No. 
C.I. 
No. 
Greenhouse 
tests 
Field tests 
First 
Second 
First 
Second 
Avena sativa L.: 
var. Green Russian_. .. _ 
I 91-4 
R 281a 
R 320a 
I 73 
C 274 
1- 
1- 
1- 
1- 
1 
2— 
1- 
1- 
1-f 
1 
var. Richland.:_ ___ ... 
787 
787 
791 
0+ 
0+ 
1 
1- 
Do____ 
var. Ruakura °. 
var. Snoma h .... 
1 
1- 
« The variety Ruakura has the same general habit as Richland but has much longer glumes. The kernel 
is whitish and the awns are few and delicate or wanting. The rust test runs from 1— to 1-f. 
1 Snoma is a gray oat of the Winter Turf type, more or less spreading, with a narrow leaf, narrow stiff 
panicle, and a few geniculate awns. 
Table III.— Data on varieties of Avena sativa orientalis of the White Tartar (White 
Russian) type which are resistant to stem rust 
Host 
Lot No. 
C.I. 
No. 
Greenhouse 
tests 
Field tests 
First 
Second 
First 
Second 
Avena sativa orientalis L.: 
var. Green Mountain... 
R 110e.... 
1872 
1 
1 
1 
1 — 
var. Long's White Tartar.... 
C 1026_ 
1 -f 
l+ 
1 -f 
1 - 
var. mutica ...... 
R 32i. 
1 
1 
2 — 
1 
var. White Tartar a .... 
R 284a_ 
551 
1 - 
1 
0 + 
1 -f 
Do...._____ 
R 301a.... 
1614 
1 - 
1 + 
1 
1 
Do......... 
I 98-4_ 
1 - 
1 - 
Do . ... 
I 1024__ 
1 
1 - 
Do... 
I 102|-5... 
1 + 
1 
2 - 
1 — 
Do...... 
I 1024-7... 
1 
1 
l 
OH- 
Do.... 
K 6096.... 
1 - 
Do...... 
C 1016_ 
1 + 
1 
1 
1 
Do...... 
R 174a.... 
1 - 
1 
1 - 
1 -f 
Do.... 
C 1020_ 
1 -f 
1 -f 
1 
Do .. . .. 
W 739.... 
**44 r 
1 
1 
0 -f 
var. Eclipse____ 
R 274a.... 
843 
3 
3+&1- 
4— 
1 —<fe4 
1 
a White Tartar is the accepted name for White Russian. 
EXPERIMENTS WITH NINE COLLECTIONS OF RUST 
At the time when this work was done (1920) physiological races of oat stem 
rust had not been reported, but their existence seemed probable. Experiments 
were undertaken in the hope of determining whether there are one or several 
physiological races of oat stem rust in California, and whether the oat varieties 
resistant to the rust collected at Berkeley are resistant to stem rust collected 
throughout the State. 
Specimens of oat stem rust were obtained from nine oat-growing districts in 
California. The shaded areas of figure 1 show the approximate distribution of 
oat-stem rust in California based on the collections of 1919, and the numbers 
mark the nine localities from which the collections cultured were obtained. 
Stock cultures of these were kept growing, isolated from each other in cheesecloth 
cages, in the greenhouse. About 40 varieties of oats were chosen, including 
