327 



On Malaceae: I. 



Pyrus coronaria L., Wilmington, Aug. 26, 1886, A. Commons. 

 Pyrus mains L., Felton, Sept. 5, 1907 (1737). 

 On Juniperaceae : III. 



Jnniperus virginiana L., Georgetown, May 18, 1892, F. D. 

 Chester; Lincoln City, May 1906, H. S. Jackson. 



The species recorded above is the common cedar-apple rust known 

 throughout the eastern United States and is one of the serious apple 

 diseases often, in epidemic years, causing- enormous losses. An account 

 of this disease in Delaware with a list of susceptible and immune varie- 

 ties has been prepared by Chester (Del. Exp. Sta. Rep. 8:63-69. 1896). 



Farlow in 1877 and 1883 (Aniv. Mem. Boston Soc. Nat. Hist. 

 35:1880; Proc. Am. Acad. 20:313, 314. 1885) was the first to attempt 

 culture work with this species. He obtained incomplete proof of the 

 life history. In 1886 Thaxter (Proc. Am. Acad. 22:257. 1887) first 

 conducted cultures establishing the genetic relation of the common apple 

 rust (Roestelia pyrata) and G. macropus. He succeeded in obtaining 

 aecia on Pyrus mahis following sowing of teliospores from J. virginiana. 

 The results were repeated and confirmed in 1887 (Bot. Gaz. 14:166. 

 1889). Halsted in 1886 (Bot. Gaz. 11:190. 1886; Bull. Iowa Agr. Coll. 

 Dept. Bot. 59. 1886) obtained infection on Pyrus loiveyisis resulting in 

 aecia. 



Stewart and Carver in 1896 (Pvep. N. Y. (Geneva) Exp. Sta. 14:535. 

 1896) conducted culture experiments in New York and Iowa and obtained 

 infection of apples in New York using telia collected in Iowa as well as 

 locally, with successful development of aecia on some varieties. In Iowa 

 infection could only be obtained on wild crab when either New York or 

 Iowa telia were used. The results are recorded in considerable detail 

 and are exceedingly interesting and difficult of explanation. 



In 1901 Pammel (Bull. Iowa Exp. Sta. 84:24. 1905) conducted 

 cultural experiments and reports infection of Pyrus lowensis and Cra- 

 taegus ))ioUis and C. pinnatifida with development of aecia using telial 

 material from both New York and Missouri. 



Arthur in 1905 (Jour. Myc. 12:13. 1906) using telial material from 

 Iowa and North Carolina obtained infection resulting in abundant pycnia 

 on the apple from both sources. In 1906 and 1907 and 1910 (Jour. Myc. 



