172 Transactions British Mycological Society. 
infected but oats were immune showing that barley cannot 
change the infection capability of this form either. 
Black rust of barley, 
In August 1g2r this rust was found at the farm with the 
infected bushes of barberry referred to in Part I. Black rust 
was noticed on Agropyron repens a few weeks earlier on the same 
farm. 
The following table shows the results of inoculations with a 
pure culture of this form. 
Hosts inoculated 
Original | Immediate 
host host A gvopyvon 
Date Barley Rye | Wheat | Oats vepens 
1921 
Sept. 4th | Barley Barley Bay 4 8 $ $ 
Archer Bey Moderate | Heavy Moderate 
Eriksson* has stated that the black rust of barley can infect 
rye and barley but not oats and wheat. Jaczewskit on the 
other hand has found that uredospores from barley can infect 
barley, Couch grass and wheat but not oats and rye. According 
to his results the forms on barley and wheat seem to be identical 
in Russia. 
Again Stakman and Piemeiself have remarked that black 
rust of barley infects wheat more readily than rye and that 
oats are not infected by it. 
It has been shown above that the black rust of Agropyron 
repens can infect wheat (Red Sudan) and rye, but the black 
rust of wheat cannot infect rye. Since the black rust of barley 
can infect rye readily and also Couch grass, it seems highly 
probable that this form is different from the form on wheat. 
Most probably the form on barley is identical with the form on 
Agropyron repens (f. sp. secalis). In the last table it has been 
shown that this form failed to infect wheat (Red Sudan) which 
is infected by the form on Agropyron repens. Unless the form 
on barley too can infect Red Sudan wheat its exact relation with 
f. sp. secalis cannot be established. Unfortunately the culture 
of this form was lost and on account of the uredo-stage being 
so rare later on it could not be re-established. Further trials 
with this were not possible. 
It is obvious that apart from slight local differences speciali- 
* Eriksson, J., Ber. Deutsch. Bot. Gesell. x11, p. 292 (1894); Zeitschr. f. 
Pflanzenkrankh. Iv, p. 66 (1894). 
+ Jaczewski, A. A., Zeitschr. f. Pflanzenkrankh, xx, p. 321 (1910). 
+ Stakman, E. C. and Piemeisel, F. J., Journ. Agr. Res. x, p. 429 (1917). 
