Pilzkrankheiten der Pflanzen 
287 
STAKMAN, E. C., A study in cereal Rusts. Physiological races 
(Minn. Agr. Exp. Stat. Bull. 138 1914, 7—56; pls. 9). 
This research is divided into two parts, the first of which is con- 
cerned with a study of the biologic forms of Puccinia graminis and the 
second with a consideration of varietal resistance. Puccinia graminis 
front Oats can be transferred to Wheat and Rye although the form 
from Barley produced only a few successful inoculations on the other 
cereals. The use of Chloroform and ether rendered the plants more sus- 
ceptible while wounds apparently had no effect. When the Rust fungus 
is grovvn continuously for successive generations on a semi-immune liost 
it appears to undergo a gradual adaptation to the new liost. When the 
liost is grown under a high state of fertilization it may exert some in- 
fluence on the breaking down of biologic forms of rusts. 
Immunity to Rust attack does not depend in the main on morpho- 
logical and histological characters but probably is to be determined only 
by biochemical studies. Among the varieties of Wheat investigated only 
two were found to possess real resistance. Only small areas of leaf tissue 
were killed on these resistant Wheats, the pustules were small and the 
spores small or abortive, Drought-resistant durum Wheats grown in very 
dry soil may Rust severely so tliat excessive soil moisture is not a primary 
factor in determining freedom from infection. The absence or presence 
of excessive amounts of fertilizer elements does not directly influence sus- 
ceptibility. F. A. Wolf (Auburn, Ala.). 
Cook, M. T. and Wilson, G. W., Clad osporium disease of Ampe- 
lopsis tricuspidatum (Phytopath. 1914, 4, 189). 
Ob man die von den Verff. beschriebene Krankheit der Ampe- 
lopsis tricuspidatum wirklich Cladosporium- Krankheit nennen kann, ist 
noch nicht sicher, denn aus dem Vorkommen des Cladosporium an ab¬ 
gestorbenen Ranken kann man noch nicht auf die Pathogenität des Pilzes 
schließen. Riehm (Berlin-Dahlem). 
LONGt, W. H., Influence of the liost on the morphological cha¬ 
racters of Pucci7tia Ellisiana and Puccinia Andropogo7iis 
(Journ. Agr. Res. 1914, 2, Nr. 4, 303—319). 
The author summarizes the research as follows: Puccinia Ellisiana 
has two widely separated aecial liost genera, Viola and Peyistemon. The 
infection of Penstemon by P. Ellisiana is vigorous and abundant. The 
characters of P. Ellisia7ia after passing through Penstemon are entirely 
changed corresponding in every essential feature to those of P. Andropo- 
gonis. Viola is also infected by P. Andropogonis and its characters 
correspond to those of the regulär Violet rust P. Ellisiana. The 
latter rust is more easily transferred from Viola to Penstemon than from 
Pe7istemo7i to Viola. The aecial liost in the case of these two rusts 
determines the spore characters. F. A. Wolf (Auburn, Ala.). 
BERGER, E. W., Citrus canker in the Gulf Coast Country, with 
notes on the extent of Citrus culture in the localities 
visited (Florida, State Hort. Soc. 1914, 1—6). 
This report was given before the Florida State Horticultural Society 
relative to the new Citrits disease known as Citrus canker. It contains 
