853 
trees and stands in a field east of Ithaca. The main part of the 
tree is normal, a single branch on the east side and low on the 
tree has much smaller leaves and acorns. The contrast between 
this branch and the rest of the tree is so marked as to be seen at 
considerable distance, and was well shown in the branches ex- 
hibited. 
Wepnespay, Aucust 26TH. Mornina. 
Prof. L. R. Jones presented some notes on potato-leaf blights, 
stating that Phytophthora infestans D. By. is common only in north- 
ern New England, northern New York and Canada. The so-called 
“Early Blight,” attributed to the parasitism of the fungus J/acro- 
Sportum Solani E. & M., is generally due not to the attacks of any 
fungus, but to arsenical poisoning, or to drought or other unfavor- 
able conditions surrounding the plant. On such dying potato 
leaves there occurs very generally a saprophytic fungus closely 
resembling Macrosporium Solani, but which in cultures develops 
quite differently. This fungus is distinctly an A/ternaria, ten or 
fifteen spores often being produced in a single chain. Macrospo- 
rium Tomato Cooke, develops exactly similar chains of spores in 
culture, and it seems probable that the A//ernaria from the potato 
leaf is the same as the tomato Macrosporium, but which should 
Properly be called Alternaria Tomato. Under especially favorable 
conditions Macrosporium Solani has also developed spores in chains, 
and hence should be known as A/ternaria Solani. 
Dr. Russell described a method of hindering the condensation 
Of water in Petri plates where agar is used asa.medium. It was 
simply to enclose culture dish in an ordinary porcelain bow] and 
cover same with a smaller inverted one. This maintains an equal 
temperature, both inside and outside of culture, thereby prevent- 
ing the accumulation of condensed water on under-surface of 
cover. 
Dr. Bessey gave an outline of the flora of Colorado Springs, 
Stating that there was here a sudden transition between the 
floras of the plains andthe mountains. In the vicinity of the town, 
at an elevation above the sea of about 6,000 feet, the plants are 
nearly the same as those about Lincoln, Nebr., which is situated 
Near the eastern side of the plains. He explained that radiating 
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