xii PREFACE. 



in its life history added. Preceding the account of tlie 

 species in eacli genus will be found a chapter on the 

 group as a wliole, followed by a Key to the species. In 

 each gi'oup of species the best known is placed fii'st, and 

 'those that follow are frequently compared' with it. 

 Many of these plants have received so little study from 

 botanists that scarcely anything is known about them. 

 In a further study of the life histories of these species the 

 beginner will find a new and inviting field in which he 

 will be a discoverer rather than a gleaner. I shall be 

 glad to receive notes of this kind, and offer to identify 

 any species that may prove troublesome, provided good 

 herbarium specimens are sent me, accompanied by post- 

 age for reply. I cannot undertake to return such speci- 

 mens, however. 



Among technical works relating to the American 

 species, first place must be given to Underwood's " Our 

 Native Ferns and Their Allies," which includes brief 

 descriptions of all but the most recently discovered 

 species in North America north of Mexico. Dodge's 

 " Ferns and Fern Allies of New Engl*nd " contains 

 somewhat more extended accounts of the New England 

 species, with an excellent chapter on the identification 

 of Isoetes and a list of the species arranged according to 

 the time each fruits. Eastman's " New England Ferns 

 and Their Common Allies," in which there are illustra- 

 tions and untechnical descriptions of a few of the com- 

 mon species, completes the list of works devoted exclu- 

 sively to the subject. Of foreign works. Baker's " Hand- 

 book of the Fern Allies," published in 1887, includes 

 short descriptions of all the species in the world that 

 were known at the time of publication. Some mention 

 should also be made of " The Fern Bulletin" now in its 



