IOWA ACADEMY OF SCIENCES. 179 



A reference to the occurrence of the disease in New Jersey- 

 is made by Dr. Halsted,* who states that the fungus is very 

 destructive to young twigs, and does its greatest damage to 

 young nursery" stock. 



Professors Barrill and Earlef do not record it under Spaero- 

 thceca castagnei, or *S'. pannosa, the form occurring upon other 

 members of the order Rosacem, nor do they mention the fungus 

 Podosphcera oxyacanthce as occurring upon Pyrus, although they 

 record it upon several species of Gratcegus. Professor Earle, I 

 in a paper on notes on North American forms of Podosphcera 

 oxyacanthce, discusses the various American forms of this poly- 

 morphic species in which he records the variability of the 

 species upon various members of genus Prunus, e. g., Prunus 

 cerasus, P. americana, P. domestica, P. padus, and describes the 

 fungus also on Spiraea tomentoscc and Amelanchier canadensis. 

 The Podosphaera oxyacanthae on Amelanchier canadensis is also 

 mentioned by Tracy and Galloway, § and likewise on two 

 species of Crataegus. 



Besseyl reports the occurrence of Podosphaera kunzei Lev., 

 which is of course synonymous with Podosphaera oxyacanthae 

 on seedling apples, frequently producing much injury. In a 

 later paper Besseyl records the same species on the apple. 



Atkinson,' in his paper on Erysipheae, from Carolina and 

 Alabama, reports Podosphaera oxyacanthae upon Crataegus punc- 

 tata, but makes no mention of a mildew on the apple. 



Dr. Davis,* in a supplementary list of parasitic fungi of 

 WiscDnsin, makes a statement that Podosphaera oxyacanthae was 

 rather common on Pyrus coronaria in 1888, and records it also 

 on Cratcegiis tomentosa. 



Trelease^ under Podosphaera tridactyla, which is synonymous 

 with P. oxyacanthae, mentions the common occurrence of this 

 species oa Prunus, but does not refer to its occurrence on the 

 apple. 



Seymour* lists the Podosphaera oxyacanthae on Prunus and 



*Rep. Bot. Dept. New Jersey Agr. Ex. Sta. 1892: 337. 



tParastic fungi of 111. State Lab. Nat. Hist. Pt. 3. 



$Bot. Gazette 9: 24. 



§Jour. Myc. 4: 34. 



II Eryslphel, Biennial Rep. la. Agr. Coll. 1877: Separate 4. 



' Bull. la. Agr. Ooll. Dept. Bot. 1884: 141. 



IJour. of EUsha Mitchell Scl. Soc. 7: Separate 9. 



2 Wis. Acad. Scl. Arts and Letters, 9: 157. 



3 Preliminary list of Parasitic Fungi of Wis. Trans. Wis. Acad. Scl. Arts and 

 Letters 6: 112. Separate 9. 



4Llst of fungi Ooll. In 1894 along Northern Pacific R. R., Proc. Boston Soo. Nat. 

 Hist. 24: 184. 



