In summarizing the examination of samples collected in this sur- 

 vey, I have attempted to meet a request for a handbook which would 

 be of use to students, conservationists, and investigators interested in 

 the taxonomy, distribution, and ecological relationships of the algae. 

 As indicated in the title, not all groups are represented here. The 

 desmids,*too numerous to be given space in this volume, merit special 

 treatment. The diatoms are being studied by Mr. Paul Conger, Re- 

 search Associate of the Carnegie Institution, Washington, D. C. 



The heterogeneity of algal groups encountered in a broad survey 

 of the flora has resulted in such a long list of species that space is 

 not available for a complete description of each one. Descriptive 

 remarks, therefore, are confined to the important taxonomic charac- 

 teristics. When reproductive structures and habits are essential for 

 identification purposes, these are described briefly. Otherwise, only 

 vegetative features and dimensions are given. I have tried to give 

 a complete bibliography of the literature in which the species were 

 originally described. Titles of treatises and of major papers recom- 

 mended for the reader who wishes a more complete discussion of 

 morphological features, reproduction, and taxonomy than is given 

 here have been marked in the bibliography. These should prove of 

 interest, especially to the less experienced student of the algae, for 

 they give a better working foundation than the local floras and older 

 handbooks can. A number of the latter are frequently used, and 

 whereas they are of value after a student has acquired some judge- 

 ment and discernment, they may be misleading if used to the exclu- 

 sion of more critical and less abridged works. Papers and books 

 which deal with or include reports on Michigan and Wisconsin algae 

 have also been given a distinguishing mark in the bibliography. 



In connection with the general descriptive remarks on the various 

 groups of algae, as they are taken up in the taxonomic portion of the 

 volume, references are made to those publications which either deal 

 primarily with particular classes or families, or which should prove 

 helpful in further systematic studies. 



SECOND EDITION 

 For this ne>v edition special attention has been directed toward 

 corrections, and the removal of inconsistencies which appear in 

 the first printing. A few keys to species have been rewritten to 

 make them clearer and more useful. Although it has not been 

 possible to include Desmids and Diatoms, an illustrated key to 

 the genera in these groups is appended. Likewise it has not been 

 possible to interpolate the many species of algae which have been 

 reported from the Great Lakes area since the 1951 printing. 



*See Appendix for key to Desmid and Diatom genera. 



