2 MYCOLOGY 



treatise is based on that of Engler and Gilg, as published in the seventh 

 illustrated edition of "Syllabus der Pflanzenfamilien," Berlin, 1912, and 

 on that of Wettstein in his "Handbuch der Systematischen Botanik," 

 Leipzig and Vienna, 191 1. Where consistent, the classificatory sys- 

 tems of these two books are harmonized and any departures which the 

 student will find from the taxonomic arrangements of Engler and 

 Wettstein have been made to simplify them by the omission of cer- 

 tain group names, or to bring the two systems into line with the facts 

 as at present known. The author has not hesitated to make changes, 

 where from his experience as a teacher, he has found it best to make 

 such alterations, especially where, for example, Wettstein uses Ordnung 

 and Engler Reihe for the same classificatory group, and where in 

 American usage order and family are used. Then, too, the author has 

 found it convenient to replace the name of a family, or order, as given 

 by Engler for one used by Wettstein, or some other author, where such 

 replacement is recommended by American usage, or where etymolog- 

 ically the name is more suggestive of the character of the group, and, 

 therefore, best for the use of students who do not expect to follow out 

 the intricacies of any system of classification. As the statements and 

 views of Engler and Wettstein are generally dependable and as their 

 classification is founded on long experience, as systematic botanists, 

 it will be found that with respect to the larger subdivisions of the 

 fungi their classifications are remarkably harmonious. The attempt 

 has been made in the pages that follow to simplify for student use 

 the facts of classificatory importance and while the groups are ar- 

 ranged in hneal sequence, it should be explained that true relationship 

 is expressed better by a family tree with main trunk, larger and smaller 

 branches. It will be noted that the arrangement of the famihes, as 

 given in the two systematic works above mentioned, are sometimes 

 reversed. The simple groups are given first place, followed by the 

 more complex. 



CLASS I. MYXOMYCETES. 

 ORDER I. ACRASIALES. 



Family i. Guttulinaceae. 

 Family 2. Dictyosteliaceae. 



ORDER IL PHYTOMYXALES. 

 Family i. Plasmodiophoraceas. 



