238 Ward,— On Relations between Host and Parasite 
2. The Rusts of the Bromes. 
In their book on the Rusts of the Cereals, published in 
1896 \ Eriksson and Henning gave detailed descriptions of 
six species of Puccinia. Of these four also occur on various 
species of Bromus. 
These are (1) P. graminis, Pers., or Black Rust, found on 
Bromus asper , P. brizaeformis , B. erectus , B, giganteus , 
B. Gussonii , B. lanuginosus , B. longiflorus , - 5 . maximus , 
P. tectorum , P. Wolgensis — all recorded for Sweden — and 
on P. mollis and P. pitensis according to other authorities. 
The Aecidium-form of this species is the classical Aecidium 
berberidis so well known since De Bary’s discovery of 
heteroecism. 
(2) P. glumarum, Schm., or Yellow Rust, found on Bromus 
adoensis , B. asper, B. arvensis , B. mollis , P. secalinus , B. sterilis , 
and P. tectorum by various authorities who have referred it 
to P. rubigo-vera. D. C. (P. striaeformis , Westd., and 
P. straminis , Fuck.) No Aecidium-form of this has yet been 
discovered. 
(3) P. dispersa , Erikss. and Henn., or Brown Rust, is found 
on P. arduennensis , P. arvensis , P. patulus , P. squarrosus, and, 
judging from herbarium specimens, on P. mollis , P. sterilis , 
and P. tectorum. 
The Aecidium-form of this species is said to occur on 
Anchusa. 
(4) P. coronata , Corda, or Crown Rust, occurs on P. asper , 
P. inermis , and P. mollis according to various authorities. 
The Aecidium-form of this species is found on species of 
Rkamnus, 
With the other two species of Eriksson and Henning’s book 
we are not concerned, since they do not occur on Bromes. It 
may suffice to note that one of them, viz. P. Phlei-pratensis , 
Erikss. and Henn., the Timothy Rust, is a species separated off 
from the old P. graminis , Pers., as peculiar to the grass 
1 Die Getreideroste. Stockholm, 1896. 
