177 



Mycologia 



sylvanica, which consume time with no more profit. They have 

 been repeatedly sown, but for want of careful field observations 

 regarding proximity of aecia, little advance is made. 



Those who assisted in the work with culture material, and often 

 with valuable suggestions, are named with special gratitude, for 

 to them is due in considerable degree whatever of value has come 

 from the year's labors. Mr. E. Bethel, Denver, Colo., sent 123 

 collections, by far the largest number contributed by one person 

 in any year since the work began. Messrs. W. P. Fraser, Pictou, 

 Nova Scotia, J. F. Brenckle, Kulm, N. D., and W. H. Long, 

 Washington, D. C, sent between 30 and 40 collections each, while 

 much smaller numbers were sent by Messrs. E. Bartholomew, 

 Stockton, Kans., J. M. Bates, Red Cloud, Neb., H. S. Coe, Ames, 

 Iowa, J. J. Davis, Racine, Wis., A. C. Dillman, Washington, D. 

 C, H. S. Fawcett, Gainesville, Fla., A. O. Garrett, Salt Lake City, 

 Utah, R. A. Harper, Madison, Wis., E. W. D. Holway, Minne- 

 apolis, Minn., Haven Metcalf, Washington, D. C, A. J. Norman, 

 College Park, Md., E. W. Olive, Brookings, S. D., J. B. Pollock, 

 Ann Arbor, Mich., Donald Reddick, R. E. Stone, and H. H. 

 Whetzel, all three of Ithaca, N. Y., Guy West Wilson, Fayette, 

 Iowa, and by Misses Louise Falk, Boulder, Colo., and Miriam 

 Turner, Isle an Haut, Me. Many living plants were received 

 from a number of botanists to whom requests had been sent for 

 suitable specimens on which to make sowings of particular rusts. 

 To all these and to others who assisted in the year's investigations 

 the writer extends his heartiest thanks. 



During the present season 294 collections of material with rest- 

 ing spores and 25 collections with active spores were employed, 

 from which 987 drop cultures were made to test the germinating 

 condition of the spores. Out of the 294 collections with resting 

 spores 134 failed to germinate, leaving 160 collections available 

 for experimental tests, this being, a far larger number than in any 

 previous year. Altogether about 400 sowings were made, using 

 a great variety of hosts growing in pots in the greenhouse, and 

 75 infections obtained. The most important conclusions derived 

 from a study of the results are given in the following paragraphs. 



Negative results. A number of collections giving good ger- 



