206 DISEASES OF FIELD & GARDEN CROPS. [CH. 



cismal or metcecious fungi is now almost beyond conception. 

 The literature is bewildering and contradictory in the 

 highest degree. The following instance is one of the 

 simplest; many others are involved almost beyond the 

 power of unravelling. 



In 1872 we observed an ^cidium invading quinces in 

 Mr. Alfred Smee's garden at Hackbridge. At that time 

 no such plant on quinces had been noticed as British ; but 

 the fungus was published by us in Mr. Smee's My Garden 

 under the name of ;E. cydonice, Lenz. We afterwards 

 learned that this fungus was considered to be a mere form 

 of Rcestelia cornuta, Tul., a parasite of mountain ash, and 

 proved (?) by experiments with spores to be a second con- 

 dition of Gymnosporangium Juniperi, Lk. Professor W. 

 G. Farlow mentions a distinct Rcestelia frequent on quinces 

 in the United States, under the name of R. aurantiaca, 

 Pk., and this is probably our plant. Professor Farlow 

 considers it a true species ; but other botanists look upon 

 it as a variety, not, however, of theR. cornuta, Tul., just 

 mentioned, but of the totally different It. lacerata, Tul., 

 whose alternate condition is said to exist in Podisoma Juni- 

 peri, Fr., a second parasite of Juniperus communis, L. In 

 the United States, strange to say, R. aurantiaca, Pk., and 

 R. lacerata, Tul., grow in company on the same host 

 plants. 



If the statements just given as to the quince fungus 

 are correct, we have two confessedly very different species 

 of fungi, both frequent on Juniper, and both able to 

 invade quinces, and produce specifically different fungi on 

 the leaves and fruit, the characters of the two quince 

 fungi being in turn so much disputed by botanists, that 

 their names are sometimes transposed, and one made to 

 do duty for the other ; each Rcestelia being supposed to 

 answer to the characters peculiar to the other one. 



Note. On page 175 we have stated that the initial experi- 

 ment of producing an ^cidium from germinating Puccinia 



