IV 



America that it seemed necessary to extend the limit of the Index 

 to species of all countries north of the Isthmus of Panama. In the 

 following pages where a species has been recorded only in countries 

 south of the United States, the name of the region where it occurs is 

 given on the right hand side of the page, but where a species occurs 

 both in the United States and regions farther south no special indi- 

 cation is given. Had it been possible, it would have been desirable 

 to include also species of the northern part of South America, but 

 the line had to be drawn somewhere, and to include South Ameri- 

 can species would have required .an additional amount of work 

 hardly warranted under the circumstances. As it is, we have given 

 all the references known to us to West Indian and Central American 

 species published in recent years, and, to the best of our ability, we 

 have inserted the species recorded from those regions in works 

 issued prior to 1888, but not included in the List of 1887 and the 

 Supplementary List of 1888. The references given from works re- 

 lating especially to the fungi of the West Indies and Central America 

 are probably comparatively complete, but it is probable that some 

 references to species of those regions originally scattered in papers 

 treating also of the fungi of other countries have escaped our notice. 

 The Sylloge Fungorum of Saccardo, of which the first volume 

 appeared in 1882, has been of the greatest assistance to American 

 mycologists in furnishing a summary of all known species, but 

 naturally in a work covering so large a field it is not possible to give, 

 except in a brief way, special references to the literature of fungi 

 in any particular country, and the Sylloge, although indispensable, 

 does not do away with the necessity of having a special index to the 

 works in which our species are recorded. The need of such an 

 index has been felt in all our universities where the study of descrip- 

 tive mycology is pursued, as well as in the numerous experiment 

 stations and other government establishments devoted to vegetable 

 pathology. In the absence of such an index it has been necessary 

 for different institutions to spend much time and money in dupli- 

 cating the work begun by us in 1874, and for a long time we have 

 wished to publish our index which, as it has been in progress for a 

 longer period than any similar index in this country, is probably 

 therefore more complete, in order that it might be used by all 

 mycologists and prevent an unnecessary duplication of labor and 

 expense. The cost of printing, however, was so great that it has 



