50 Rhodora [March 



prostrate forms of the large ferns are exposed to view, and then is a 

 good time to study the crowns and crosiers. 



Then too is a good time to searcli for abnormal forms of the poly- 

 pody, which in England produces so many remarkable variations. 

 Among the countless thousands of plants distributed throughout our 

 New England woodlands one may well expect to find many interest- 

 ing forms, which, while they might not be of any great importance 

 from a taxonomic standpoint, would yet be of some interest biologic- 

 ally, and help to increase our knowledge of the causes for plant 

 variation. 



It may be objected to the treatment adopted in this study, that, 

 being based largely on the character of the rootstock, it may lead to 

 the extermination of rare ferns by the taking up of plants ; but this 

 need not necessarily follow. The rootstocks of nearly all of our ferns 

 can be studied without disturbing them enough to retard their growth, 

 and with proper precautionary instructions it will be found that those 

 who realize the importance of protecting and preserving our native 

 plants will be less liable to destroy them through this method than 

 they would be through any other. Thus this method may even 

 become a valuable medium for aiding in the preservation of rare 

 plants. 



Roughly grouping our New England Ferns by their most obvious 

 characters for the convenience of a ready recognition we may separate 

 them into two sections as follows : — 



I. Evergreen, or partially so, at least as to the late sterile fronds. 

 Fronds more or less persistent through the winter. 



II. Not evergreen. Fronds withering away on the approach of 

 winter. 



These sections may each be subdivided into three divisions based 

 on the nature of the rootstock in accordance with the following 

 arrangement. 



Division A. — Rootstock rhizomatose, i.e., having the charac- 

 ter of a rhizome — a running stem. Fronds more or less scattered ; 

 crosiers (frond-buds) usually isolated. 



Division B. — Rootstock caudiciform, i. e., short, stout, and hav- 

 ing the form of a caudex. Fronds fasciculate, i. e., clustered at the 

 growing end. Here occur two forms namely: with the rootstock, 

 in the one case, erect, or partially so, growth upright ; and in the 

 other, decumbent, growth lateral, extending horizontally. 



