Professor Marshall Ward, On the Question of 
on further growth of the species of Bromes investigated, and to 
examine certain anatomical points. These results may he sum- 
marised as follows : 
More than 2000 infections have been made on 22 species and 
varieties of Bromus, principally seedlings, carefully selected and 
cleaned and grown in pots under conditions in most cases so 
satisfactorily controlled that the rust-pustules only appeared (with 
very rare exceptions) on the spots where the sowings of spores on 
the leaves were made. These 22 species and varieties belonged to 
four out of the five sub-genera of the genus, viz. Festucoides, Steno- 
bromus, Serrafalcus and Oeratochloa: I have not yet been able 
to experiment with B. arduennensis representing the sub-genus 
Libertia of Hackel. 
In order to illustrate the nature of these infection experiments, 
let us take the following series from among the latest of those 
made during the past summer. 
Series Numbered 735, 736 and 738. (Table I.) 
The pots of seedlings were all under like conditions and in- 
fected similarly, by means of uredospores gathered separately and 
kept separate, and known to be vigorous on germination. 
The annexed Table I. summarises the facts. 
On comparing these results we find no room for doubt as to 
their meaning. The spores employed were in all cases germinating 
well : the infections were made at the same time, and the con- 
ditions Avere in every respect — including the age and treatment 
of the seedlings before infection — alike. 
Nevertheless, Ave find as I had frequently found before 1 , that 
spores from B. sterilis, Avhile successfully infecting B. sterilis and 
its ally B. madritensis , failed on all the other plants of the series. 
On the other hand, the spores from B. mollis infallibly picked out 
their oaaui species and its allies B. velutinus, B. commutatus , B. ar- 
vensis, B. secalinus, B. interrupts and B. racemosus , but failed on 
B. sterilis and its allies B. madritensis and B. maximus. 
Series Numbered 741 and 744. (Table I.) 
In the experiments where spores from B. secalinus Avere em- 
ployed for inoculation Ave meet Avith exactly similar facts, only 
here the fungus attacks B. secalinus by preference and B. arvensis 
next in order. B. sterilis, B. maximus, B. madritensis, on the 
other hand, as also B. velutinus, B. interruptus and B. racemosus, 
Avere either entirely immune — to all appearance — or Avere only 
attacked very slightly. 
1 Details of the conditions and results of other experiments are in course of 
publication. 
