PAPERS GIVING RUSTS OF NORTH AMERICA. 183 



terial of Schweinitz's forty-two numbers under Puccinia in the 

 autographic packets and also in other herbaria. Dr. Farlow states 

 that 32 of these numbers are represented in the Herb. Curtis at 

 Harvard University and Dr. Shear writes that there are 37 in the 

 Michener collection at Washington. 



The senior author has consulted the part of the Schweinitz col- 

 lection containing the rusts a number of times between 1899 and 

 1917, for a few hours or a few days each time, as other duties de- 

 manding a visit to Philadelphia or nearby cities permitted. The 

 first visit of three hours' duration was on Feb. 17, 1899, and a second 

 one of about the same length of time on Aug. 4, 1900. At this 

 second visit the impossibihty of satisfactorily deciding upon the 

 identity of many of the collections without better microscopic facili- 

 ties and more time than could be hoped for while in Philadelphia 

 w^as forced into prominence. A bit from an ample specimen, such 

 as would furnish a few spores for examination under the micro- 

 scope, could be carried away when the need was great, without a 

 feeling of having done harm to this precious historical collection, 

 but many specimens were too meager for such liberties. About a 

 score of specimens of the unmounted material were selected at this 

 time which most needed study and a request left to have them sent 

 to Lafayette, Indiana, for more careful examination. But the 

 authorities of the Academy had become wary, their attention having 

 been called recently to the mysterious hiatus in the mounted set, 

 including the important genus Puccinia, and had decreed a general 

 ban on all loans. It was not until 191 5 that the regulations were 

 so far modified that the privilege was obtained to study these speci- 

 mens microscopically for a few days in April of that year at the 

 laboratory in Lafayette. 



During the four days of December 28-31, 1903, many hours 

 were spent in consulting the collection, at which time the senior 

 author was assisted by Dr. Frank D. Kern, and again much study 

 was given the collection during the five days of December 28, 1914, 

 to January i, 1915, assisted by Dr. F. D. Fromme. The senior 

 author also consulted the collection on February 5-12, and April 

 11-14, 1917, Dr. C. L. Shear being present part of the time during 

 the April period and giving valuable assistance in interpreting the 



