152 Lvansactions British Mycological Soctety. 
wheat early in spring usually a little later than the yellow but 
long before the black rust. Butler* has stated that in India it 
is the earliest to appear on wheat. The uredo-sori of this rust in 
summer resemble those of black rust on leaves and are often 
mistaken for them. 
Wardj, Carleton{, Hitchcock and Carleton§, Bolley|| and 
others to whom reference has already been made have pointed 
out that the uredospores of brown rust can be found during 
winter. The following is a brief summary of the observations 
made by the writer. 
(I1g20-21.) There was plenty of the uredo-stage of the rust on 
self-sown wheat in October and November but after a heavy 
frost in December it was very rare for a period of two months 
though not altogether absent. By the third week of February 
it again became quite common on self-sown wheat. For the 
rest of the season up to the harvest time the rust was plentiful 
on the wheat crops. Barley was observed to be heavily in- 
fected by P. simplex and the brown rust of rye too was very 
common. 
(1921—22.) After the harvest of 1g21 it was observed here and 
there round Cambridge and the brown rusts of barley and rye 
were also noted on self-sown plants. During autumn and the 
whole of winter the rust was not difficult to find on wheat except 
for a short time in January 1922 when it was rather rare. 
P. simplex was also noted on barley occasionally. By the middle 
of March it had established itself on the crop and was very 
common in summer (1922) up to the harvest time. 
In addition to the above may be quoted some interesting 
observations, made on a small plot of Luther Burbank wheat 
(a very susceptible variety) sown at the Botanic garden on 
August loth, 1921. This plot was kept under frequent observa- 
tion. Throughout the season (1921-22) brown rust was found 
on this plot. Fresh uredo-sori were, however, rather rare in 
the latter half of January after frost. It is of interest to note 
that this plot showed no yellow rust for a period of over ten 
months. 
As far as this rust is concerned, it may safely be stated that 
for the period the data cover it is transmitted from season to 
season by uredospores. 
We cannot, however, take the last two winters as anything 
* Butler, E. J., Fungi and Disease in Plants (1918). 
¢ Ward, H. M., Ann. Bot. xix, p. I (1905). 
i Carleton, M. A., U.S. Dept. Agric. Div. Veg. Phys. and Path. Bull. No. 16 
1899). 
§ Hitchcock, A. S. and Carleton, M. A., Kansas Agric. Coll. Exp. Stat., 
Bull. 46 (1894). 
|| Bolley, H. L., Centralbl. f. Bakt. 1v, Abt. 2, p. 893 (1898). 
