26 195 



Mycologia 



April 1 6, on Crataegus cerronis A. Nels., giving rise to numerous 

 pycnia April 25, and equally numerous aecia May 23. 45 



32. Gymnosporangium Nelsoni Arth., on Juniperus virgini- 

 ana L., sent by Professor R. A. Harper from Merrimack, Wis., 

 was sown May 2, on Amelanchier ere eta, Cydonia vulgaris and 

 Mains coronaria. Infection was only on Amelanchier, showing an 

 abundance of pycnia May 1 1, and equally numerous aecia June 8. 46 

 This rust is not often seen east of the Rocky Mountains. The 

 witches' brooms which are produced have a general resemblance 

 to those of G. nidus-avis, and it may sometimes be confused with 

 that species. 



33. Cronartium Quercus (Brond.) Schrot. Aecia (Peri- 

 dermium Cerebrum Peck) on Pinus virginiana Mill., were sent by 

 Mr. W. H. Long, from the vicinity of Washington, D. C, and 

 sown April 28, on Quercus rubra. The first appearance of ure- 

 dinia was not recorded, but on May 20, a few uredinia and many 

 telia were observed. 47 



34. Melampsoropsis abietina (A. & S.) Arth., on Ledum 

 groenlandicum Oeder, sent by Professor W. P. Fraser from 

 Pictou, Nova Scotia, was sown June 15 on Picea Mariana (Mill.) 

 B. S. P., giving numerous pycnia June 23, and aecia about August 

 12. This connection was first suggested by the field observations 

 of Anton de Bary in the Alps, and by him proven by means of 

 cultures in 1879. 48 A number of field observations by other 

 mycologists were recorded, tending to fortify the result, but no 

 other cultures were made until 1901, when Klebahn 49 verified the 

 work of de Bary. 



The probable connection of Ledum and Picea rusts in America 

 was discussed by Professor W. G. Farlow in 1885, 50 based largely 



45 For previous cultures see Jour. Myc. 14: 23. 1908; Mycol. 1: 240. 1909; 

 and 2 : 230. 1910. 



4 *For previous cultures see Jour. Myc. 13: 203. 1907; 14: 18. 1908; and 

 Mycol. 1 : 239. 1909. Studies published by Dr. F. D. Kern (Bull. N. Y. Bot. 

 Gard. 7: 448. Oct. 191 1) since this article went to press show that the form 

 used in this culture, and also in the previous ones here referred to, has been 

 erroneously referred to G. Nelsoni, it should be called G. juvenescens Kern. 



47 For previous cultures see Jour. Myc. 13: 194. 1907- 



48 Bot. Zeit. 37: 802. 1879- 



49 Zeitschr. Pflanzenkr. 12: 17. 1902. 



M Proc. Amer. Acad. Sci. 20: 320. 1885. 



