XXX 
INTRODUCTION, 
bell glass, or other glass cover, excluding, as completely as 
possible, communication with the outer air. In a few weeks 
the young Ferns will come up abundantly, in a sinuous 
horizontal frond, closely resembling that of Marchantia ; 
but in a very short time other fronds will succeed, having 
the true characters of Ferns. 
In my descriptions I have endeavoured, as far as practi- 
cable, to combine simplicity with uniformity. I am aware 
that some readers may possibly object to the occurrence of 
Latin or technical words, but these are never used when a 
common English word would answer the purpose. I think 
it must be obvious to the understanding of every one that 
it is needful to have a term that shall he sufficiently precise 
to express what is intended, and I believe our best bota- 
nists aim at nothing more, although they are frequently 
charged with the invention of unintelligible words. I trust 
that the technical words used in the present volume will 
be found not only few in number, but will be rendered 
perfectly intelhgible by the following explanation. I have 
treated every fern as having three parts, — the roots, the 
rhizoma, and the fronds : if the reader will turn to pages 
93, 115 and 131, he will see examples of these three parts ; 
in every instance the worm-like stem running horizontally 
or across the page is the rhizoma ; the upright stems which 
ascend from this, together with the apparent leaf at their 
summit, are the fronds ; and the fibres are the I'oots, The 
rhizoma in all these instances is said to be creeping, and is 
in fact an underground stem : when this is the case the 
