DoDGE: STUDIES IN GENUS GYMNOSPORANGIUM 295 
Twelve red cedars were sprayed with spores from G. nidus-avis 
on Amelanchier in 1916. Only three of the plants have become 
infected, one of these in five different places. Cedar No. 414 was 
inoculated with spores from Amelanchier No. 878, June 11, 1916. 
Three small tongue-shaped sori were found among the young leaves 
of a side branch on April 5, 1917. This branch has since died. 
Cedar No. 929 had not been exposed to infection since 1913. 
The original teleutospore material with which the experiment was 
begun was obtained at Fort Lee, New Jersey, May 10, 1916. 
The infected branch, about two inches in diameter, had a very 
rough appearance and was covered with corky mounds and 
swellings. The sori when swollen were tremella-like and about an 
inch long. Amelanchier “‘canadensis’’ No. 878 was sprayed 
May 14. Spermogonia appeared on the leaves May 21, and aecidia 
were fully matured on the fruits June 9. Only a few aecidia 
developed on the leaves, although they had previously borne 
a great many spermogonia. No. 929 cedar was then sprayed 
with aecidiospores June 9; it was put in the cold frame October 22 
and taken out March 7, 1917. A swelling and distortion of the 
main stem at the tip was plainly visible about November 1, al- 
though no sori had been noticed during the early months of spring. 
This plant was brought back to the green house again January 6, 
1918. Sections of the swollen region were made January 17, 
1918 and showed two annual rings of wood and two developing 
sori. No callus scars have been found on these sections, showing 
that a sorus had developed in 1917. In this case the resulting 
infection was just about of the type we should expect, and we can 
imagine it might have in years come to look much like the original 
infection with which we started. Photographs and specimens of 
all stages have been preserved. 
The history of the infection of cedar No. 609 is more interesting. 
The teleutospore material was obtained from the largest infected 
red cedar on the grounds of the New York Botanical Garden. 
The trunk of this tree is heavily infected for a distance of several 
feet and has developed a large spindle-shaped swelling three feet 
long about ten feet above the ground. Amelanchier “ canadensis’ 
No. 886 was sprayed May 17, 1916. Spermogonia appeared May 
26 and aecidia ripened on the fruit June 12. Red cedar No. 609 
