DopcGE: STUDIES IN GENUS GYMNOSPORANGIUM 293 
TABLE V 
INFECTION OF Juniperus communis WITH G. clavariaeforme 
No. Date of inoculation sei 7 cau w noted 1017 Results January 7, 1918 
I916 
925 June 10 Plant died gee 
026 June 6 dl infectio f Plant died 1917. 
931 June 6 e infec rosa Two infections. 
932 June 6 No: signs of infection. Plant died 1917. 
9033 une 6 Soaee Cong es “e One infection. 
959 June 29 Two infections, lost Three infections. 
many leaves. 
June 29 No signs of infection. One infection. 
961 June 29 One infection. Two infections. 
962 June 29 No infection. No infection. 
There were nine separate infections in all. One of the plants 
from New Hampshire was not infected. The two control plants 
remained uninfected. Sections of three of the swollen stems were 
made January 17, 1918, ten days after the plants had been taken 
from the cold frame. It was found that teleutospores were being 
formed, although the sori had not yet broken through the bark. 
In sections even at the lowermost points of the swellings there 
appeared only two annual rings of wood. There were at first no 
signs of infection but minute sori with a few spores each developed 
on three of the plants during the last of April, 1917. The fact 
that sori formed the first year may be so small as not to break 
through the cork or epidermis, and therefore not be detected, 
should always be considered. Sections made the next year will 
show the cork callus at the point where the sorus was located. The 
infection of these plants undoubtedly occurred on the new growth 
of the spring of 1916. These cultures do not furnish much evi- 
dence that, as Plowright maintains (9), sori are not produced the 
spring following the year of infection. Tubeuf (10) gives a de- 
tailed and quite convincing account of his cultures of the species 
and there is no doubt that the incubation time may vary. This 
period does not appear to be absolutely fixed in the case of the in- 
fection of the red cedar with G. clavipes and G. Ellisii, which the 
writer has previously noted, and it will be shown later that the in- 
cubation time varies when cedars are infected with G. nidus-avis. . 
