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leaves first iufected , while the leaves of those iufected May 28 
withered and ultimately feil off from no apparent cause. The re- 
maiuing plants yielded no result whatever. 
July 10. Peridia began to show on the two apples first mentioned 
as affected. These developed slowly, and towards the end of July 
were recoguizable as belonging to the Aecidium pyratum of 
Schweinitz. It did not however assume the penicillate form pecu- 
liar to this Roestelia until exposed to the weather; when the 
peridia, formerly long and barely lacerate, were turned back in 
the cliaracteristic fashion. 
G. clavariaeforme. 
April 30. Sporidia sown on 
3 Pyrus American a. 
3 Pyrus malus. 
May 11. No result, and the same plants reinfected with the addi- 
tion of 
3 Crataegus tomentosa. 
May 18. Spermogonia appeared on each Crataegus. 
May 30. Signs of aecidia on all the leaves affected, localized on the 
midribs and veins. 
June 2. Peridia began to show, which in about a week developed a 
Roestelia, having the microscopic characters of lacerata (the 
form subsequently spoken of as lacerata, x), while the peridia 
were but slightly lacerate and resembled those obtaiued from the 
macropus culture before exposui’e to the weather. With the 
remaining plants no result was obtained. 
G. globosum. 
April 30. Sporidia sown on 
3 Crataegus coccinea. 
3 Pyrus American a. 
3 Pyrus malus. 
May 9. Spermogonia appeared abundantly on all the Crataegus 
plants, on a single leaf of Pyrus Americana, and on one apple. 
May 16. All plants that had not produced spermogonia were rein- 
fected without result. 
June 2. Sporidia sown on 
1 Amelanchier Canadensis. 
June 12. Spermogonia on Amelanchier, not in great abundance. 
This plant was accidentally destroyed late in June, at which time 
it sliowed no signs of aecidia, while the remaining plants affected 
conti nued to produce spermogonia until late in July, when the 
leaves withered and feil off. 
G. biseptatum. 
May 30. Sporidia sown on 
2 Amelanchier Canadensis. 
1 Pyrus arbutifolia. 
June 12. Spermogonia on both Amelanchiers, the Pyrus not affected. 
Towards the end of June there were slight indications of aecidia in 
most of the affected leaves. The development of the Roestelia 
was very slow; and though the bulbous base of R. botryapites 
