Notes on Recent Literature. 
103 
memoirs dealing with vegetation on broad “ primary ” lines. The 
Caithness memoir introduces into studies on vegetation, the 
importance of the topography of a district on the distribution of 
plants both now and in the past. It also includes as a major theme, 
the distinction of plant formations (e.g., moorland) on relatively 
stable geological substrata, and the more transient associations 
on unstable substrata, such as those presented by the erosion and 
deposition by rivers and seas, or by tbe climatic factors so actively 
at work amongst arctic-alpine vegetation. Owing to the conditions 
of the grant this paper cannot be purchased, but it has been widely 
distributed, and applications to the the author (or to the Secretary 
of the Committee, 13, George Square, Edinburgh), will be 
considered. 
Numerous other publications by members of the Committee 
have appeared in the various periodicals, but these need not be 
specifically recorded. 
Altogether the British Vegetation Committee has passed 
through a somewhat eventful period, the prelude, it is hoped, to 
even greater and more widespread future activity. 
VV.G.S. 
NOTES ON RECENT LITERATURE. 
RUST FUNGI 
The Wintering of Puccinia grnminis. 
Pritchard 1 discusses the various possible means by which 
Puccinia grnminis survives the winter and causes infection of the 
wheat fields of the northern part of the United States year after 
year. He considers that the aecidiospores play a relatively small 
part in the dissemination of the fungus, for he found that the 
direct influence of infected Barberry bushes was confined to a 
distance of 100 yards. Furthermore he experienced considerable 
difficulty in artificially infecting wheat plants with aecidiospores. 
It is well-known that the Barberry is by no means always necessary 
for the propagation of the black rust of cereals, because no infected 
Barberry bushes have ever been found in Australia and Ecuador 
where this rust is prevalent. According to Pritchard the uredo- 
spores do not retain their vitality over tbe winter in the State of 
North Dakota, so that this source of re-infection is excluded. 
Uredo pustules appear on winter wheat there as early in the year as 
upon wild grasses, and therefore the latter can hardly be looked 
upon as the source of infection of the wheat plants. 
' Pritghard, F. J, Bot, Gaz., 1911, Vol. 52, p. 169, 
