170 Transactions British Mycological Society. 
capabilities of the biologic forms that he worked with were 
constant. 
Black rust of Agropyron repens (P. graminis secalis). 
This biologic form has been found only on Couch grass 
(Agropyron repens) in this locality. It is probable, however, 
that the form found on barley which will be dealt with later is 
identical with it. The following table gives the results of inocu- 
lations with uredospores. In experiment No. 1 the material 
used was such as had been cultivated on Couch grass for one 
generation. In other experiments the material used had been 
cultivated on rye for two, three, five and six generations 
respectively. 
Hosts inoculated 
Agvopyyon 
Date vepens Rye Wheat Barley Oats 
1921 
Aug. 11th Po 6 R+ Baoie 0 
Moderate Heavy Very weak Good 
En ¢ Bos & 
Aug. 30th —— 4 Rz Bag % 4 
Heavy Very weak Good 
Sept. 13th — a R 2 Bg, # 4 
Heavy Very weak Weak 
1922 
Jan. 24th ar 35 Riv B, <5 12 
Heavy Very weak Weak 
J 2s 
Feb. 25th = 42 R -8, B, £ — 
Heavy Very weak Weak 
J 10 By; 10 
Weak 
Nore. The varieties used are the same as tried with the biologic form of 
wheat. For the cultivation of this form seedlings of rye were found to be 
more convenient than those of Couch grass (the original host). 
Along with the first experiment seedlings of Dactylis glo- 
merata, Lolium perenne, Arrhenatherum avenaceum and Hordeum 
gubatum were also inoculated but none of them became infected. 
Eriksson* has found that this form infects rye, Agropyron 
repens, Hordeum jubatum, barley and some of the grasses but 
not wheat and oats. Eriksson and Henningy have recorded that 
inoculations with material from rye infected rye and barley but 
not oats and wheat. Jaczewskif{ in Russia has remarked that 
Dactylis glomerata can be infected and that barley, wheat and 
oats are immune. 
* Eriksson, J., Ber. Deutsch. Bot. Gesell. x11, p. 292 (1894). 
{+ Eriksson, J. and Henning, E., Die Getreideroste (1896). 
t Jaczewski, A. A., Zeitschr. f. Pflanzenkrankh, xx, p. 321 (1910). 
