261 



SUSCEPTIBILITY AND IMMUNITY OF DIFFERENT SPECIES OF 



APPLES. 



Some observations were made in different parts of the city to de- 

 termine the susceptibility and immunity of different species of apples. In 

 the experiment already described the apple tree infested was of the 

 Milum variety. In the same yard in which this tree stood was another 

 apple tree that was never infected by the rust. It was a fall apple, 

 variety unknown. In another yard in another part of the city stood two 

 apple trees with interlocking bi'anches; one was of the Bellflower variety, 

 a winter apple, the other was a large fall apple, variety unknown. Across 

 the 'street to the west stood two cedars that usually bore a few galls. 

 The Bellflower always suffered severely from attacks of the pest, while 

 the other tree remained free from it. The difference in the appearance of 

 these two trees by the middle of August was most striking. The Bell- 

 flower, with its sickly, yellowish foliage, mottled with the dark clusters 

 of Eoestelia, presented a striking contrast to the dark, healthy green of its 

 neighbor's. The effect was also very noticeable in the apples of the two 

 trees. Those of the Bellflower were small, knotty and not numerous, 

 although the branches had been loaded with blossoms during the spring. 

 The apples of the other tree were large, perfect and plentiful. More 

 extended observations regarding this point will be made next spring. 



The selection of immune varieties seems to be the only solution of the 

 problem of the extinction of the fungus, at least in this vicinity. Not only 

 do cedars occur in the natural forests of the region, but they have been 

 very generally planted by farmers for protection and decoi-ation so that 

 the only other method, the destruction of the cedars, is quite out of the 

 question, as so many not concerned in apple gi'owing would not destroy 

 their cedars, and the absolute destruction of every red cedar would be 

 necessarv to exterminate the fungiis. 



Notes on the Genus Steimonitis. 



H. H. Whetzel. 



During "the past summer and fall we have made a careful study of the 



genus Sremonitis, as represented by the species occurring in the vicinity 



of Crawfordsville. Ind. This study has brought out several striking and 



interesting conditions regarding the development of some structures of 



this genus. The study was made in the laboratories of Wabash College, 



15— Academy of Science. 



