150 Transactions British Mycological Soctety. 
and also yellow rust here and there. On the 24th of June for 
the first time in the season Couch grass just below infected 
bushes of barberry was seen covered with uredo-sori of black 
rust. By the middle of August the disease had spread to barley 
as well. The attack was a mild one and rusted plants were 
observed only within ten to fifteen yards of the hedgerow. By 
the third week of October the uredo-stage became very rare and 
during winter and the following spring (1922) no uredo-stage 
could be found. 
Towards the end of May ripe aecidia on barberry were again 
noticed at the same farm. A fortnight later the uredo-stage was 
quite common on Couch grass just below the infected bushes of 
barberry. By the end of July the rust had spread on Couch grass 
over a considerable area, the weather being very favourable. 
One could safely attribute the exceedingly restricted and mild 
nature of the attack of black rust as recorded above and its 
complete absence at the University farm, last year (1921), to 
the exceptionally dry and warm weather during the latter part 
of spring and the whole of summer. Undoubtedly the weather 
conditions were most unfavourable, both for an extensive in- 
fection by the aecidiospores and also for the spread of this rust 
by the uredospores. This probably explains why black rust was 
conspicuous by its absence last summer at the University farm. 
It may be pointed out that last summer wheat and barley were 
simply covered with yellow and brown rusts which it must be 
remembered had already established themselves during the 
earlier part of the year. 
(e) Inoculation experiments with sporidia. 
Eriksson and Henning* while denying the possibility of the 
survival of uredospores through the winter have attached special 
importance to the view that teleutospores may on germination 
cause direct infection of graminaceous hosts by their sporidia. 
In the spring of Ig2I some inoculation experiments were 
conducted on young seedlings of wheat to see if they could be 
infected with sporidia of P. graminis tritici. 
From the 22nd of February up to the 6th of April several 
germination tests were made with teleutospores that had been 
kept in the open throughout winter, and they invariably showed 
good germination. On the 6th of April two plants of barberry 
(as control) and many young seedlings (six days after sowing) 
of wheat were inoculated with teleutospores mixed in water. 
On the fourteenth day inoculated leaves of barberry showed 
spermogonial patches. Seedlings of wheat showed only brownish 
* Eriksson, J. and Henning, E., Die Getreideroste (1896). 
