EXPERIMENT STATION REPORT. 419 



NOTES UPON SOMG RUSTi AND MILDEWS AT 

 "WERNERSVILL.E, PA. 



While sojourning for health at Wernersville, Pennsylvania, during 

 several weeks in the spring, some observations were made upon the 

 parasitic fungi of that region. 



Evsts. — Among the first of the rusts to appear was an Aecidinm 

 upon Banunciilus abortivus. This host is very common in the open 

 "woods, and the rusted plant is easily detected by the small, spade- 

 shaped leaves, that stand up edgewise upon long, slender petioles. 

 The diseased plants last for only a week or so after the cluster eup^ 

 appear, thickly covering the under side of each leaf. The fungus 

 seems to destroy all the portion of the plant above ground, and while, 

 during one week, the display of rust is extensive, at the end of the 

 next there is little left excepting dead leaves. 



There were some small quince orchards in the region, and one in 

 particular was bordered upon two sides by a hillside covered with 

 cedar trees. In some instances the branches of the quince trees and 

 those of the cedars interlocked. The cedars bore an abundance of the 

 large, yellow galls commonly known as ""cedar apples." These are the 

 consjDicuous formations of the rust fungus known as Gymnosjiur- 

 angium macropus, and in another form does much damage to the apple 

 leaves and fruit. Upon the same cedar trees was an abundance of 

 another species of Gymosporangium (G. glohosum). This does not 

 produce spherical galls like the one first mentioned, but causes a 

 swelling of the small branches until they are somewhat spindle-formed, 

 and become covered with an orange coating at the time when spores 

 are set free. Upon the quince leaves, before they were full-sized, the 

 rust appeared in considerable quantity, sometimes occupying all of 

 the under surface when the numerous clusters of deep cups were pi'o- 

 duced. Later on the fruits probably became infested, for the mummy 

 fruit of the previous year showed that the fungus had destroyed them. 

 This Roestelia auraratiaca, as the orange rust of the quince is some- 

 times called, botanically, might be reduced by separating the two host 

 plants of the fungus by cutting away the cedars near the orchards or 

 exercising care in setting quince trees apart from the cedars. 



The ash trees showed conspicuously the rust (Aecidium Fraxini) 

 that is common to the species of Fraxiniis. In the present instance 

 some ash trees were entirely free, while others of the same species had 



