232 



Mycologia 



ciate, Dr. F. D. Kern, who for ten years took part in the cul- 

 ture work. The grass and sedge rusts were, however, the ones 

 that received the most extended and prolonged attention. 



To carry on the work more than 2140 collections with resting 

 spores were available, together with over 250 collections with 

 spores not requiring a resting period. Tests of all of these, and 

 of some many times repeated, showed that not all were viable, 

 at least at the time tested, and therefore not serviceable. This 

 material was provided in part by those directly connected with 

 the work, and to a considerable extent by more than 85 botanical 

 correspondents, many of whom contributed most generously in 

 material and field observations year 'after year. Altogether 

 about 3750 sowings, that is, attempts at cultures were made, of 

 which about one in seven resulted in successful infection of the 

 host. These tests were almost wholly made in a greenhouse, al- 

 though a few were conducted in the open field when small plants 

 suitable for placing in pots were not available. 



It is difficult to say just how many species have been grown 

 through some part of their life cycle during the nineteen-year 

 period, owing to the constant shifting of accepted names as 

 knowledge regarding them accumulated. Probably the list in- 

 cludes about one hundred species, as they are now rated, or nearly 

 twice as many as they would at first have been listed, and of 

 this number about eight were heteroecious to one autoecious. Of 

 the heteroecious species some twenty were verifications of com- 

 binations previously established, mostly by European investiga- 

 tors, while about sixty-five provided alternate hosts for species 

 whose life cycle was before unknown, most of these being grass 

 and sedge forms not known outside of North America. 



When viewing the present location of the New York Botanical 

 Garden many years ago, it then being a rolling meadow without 

 buildings of any kind, my companion, Professor L. M. Under- 

 wood, remarked that some day I might be called upon to supply 

 the rust portion for the projected North American Flora, and 

 added that if I did so he had no doubt that I would greatly 

 reduce the number of species. The culture studies have enabled 

 me to do this, but not quite in the way Professor Underwood 



