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proceed to explain my own, incorporating occasionally the valuable 
observations of the authors I have named; for I believe it impossible 
to study, and appreciate, and accept as true the labours of others, 
without their becoming so engrafted on your own that it is difficult, 
if not impossible, to restore each idea to its original owner. So small is 
my desire to be regarded a discoverer or innovator on this interesting 
question, that I would hare adopted the method of either of the great 
botanists I have mentioned far rather than proposed another, had 
either of them united the two great desiderata—Ist, of making the 
application of the theory general; 2ndly, of carrying out the same 
theory in detail. 
My own misgivings as to the value of the involuere in classifying 
ferns date from 1837, when I first attempted the study of the British 
ferns. These misgivings first found expression in print in this Joure 
nal, in 1842, and were systematized with some precision in the Intro- 
duction to the third edition of the ‘ History of British Ferns,’ in 1854. 
Up to that period I was in total ignorance of Gaudichand’s views, 
and was so far mistaken in Mr. Smith’s as to suggest that my divisions 
Rhizophyllacez and Cormophyllacez were equivalent to his divisions 
Eremobrya and Desmobrya; whereas his subsequently published 
system, as already stated, shows that Mr. Smith’s Eremobrya equals 
my genus Ctenopteris, and his Desmobrya my genera Gymnocarpium 
and Psendathyrium united. I am quite ready to admit that my views 
have undergone considerable alteration and modification during the 
twenty years that I have been applying myself to the subject, and 
therefore that a critic might discover discrepancies in my printed 
opinions ; but I have ne more idea of regretting or apologizing for 
these alterations and modifications of opinion than I have far the very 
obvious truth that [ am twenty years older now than when I began. 
Part I1.—The New Method. 
Plants, generally speaking, are composed of four obvious parts— 
roots, stems, leaves and flowers. The roots, stems and leaves seem 
to subserve the offices of support, nutrition and respiration; in a word, 
to be provided for the preservation of the individual: the flowers seem 
to subserve the office of generation alone, and therefore to be pro- 
vided exclusively for the preservation of the species. Now, these 
purposes are absolute requirements in all created beings, and are as 
