f ..No, I2. 3 



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EVENING SESSION. 

 Wednesday, January 20, 1886. 



The meeting was called to order at 7 o'clock by President Smith. 



The following lecture was then delivered by Prof. A. B. Seymour, 

 of the State University at Madison, Wisconsin : 



SOME FUNGUS DISEASES OF SMALL FRUITS. 



Mr. President, Ladies and Gentlemen: 



Before speaking of any particular disease, I wish to show how and 

 why fungi produce disease in plants. It is well known that the green 

 coloring matter occurring in all our common plants has the power of 

 converting inorganic matter taken from the soil and air into food, 

 materials for the plant. All plant food and indirectly animal food is 

 produced in this way. The plants known as fungi, however, have no 

 leaf-green and therefore are not able to provide themselves with food 

 from soil and air. They must derive their nourishment from either 

 living or dead organic matter. 



Different kinds of plants grow on different soils. Fungi choose 



places of growth in much the same way that other plants do, but much 



~>re closely. Some grow on almost any decaying vegetable matter; 



i wood of some particular tree. A very large num- 



iving plants and commonly each species only on 



rticular family or species. Wheat rust grows on* 



e orange rust of berry plants, only on raspberries 



while corn rust is not known to occur on any plant 



" ~ . 

 ngi come from? How do they get there? They never 

 aneously but always from reproductive bodies called 

 ing the purpose of seeds. These are very minute and so 

 r are borne in the air like dust, and some kinds are ear- 

 Under favorable conditions if they are brought to the 

 :' plant, as corn smut spores to corn, they germinate and 

 ender tube which answers the purpose of a root, and makes 

 the plant, often through breathing pores. Once inside, it 

 branches, sending its threads in various directions among 

 cells. Frequently special branches are produced, which 

 the cell cavities and act as suckers to take up nourishment. 

 angi have different stages of development, reminding one 



