J. SMITH ON THE GENERA OF FERNS. 39 



views of that genus so nearly coincided with those of Mv 

 Brown, which were shortly afterwards published in the Flora 

 Javanica. 



I had nearly completed my arrangement when I received a 

 copy of Presl's " Tentamen Pteridographice," a work published 

 at Prague in 1836, but not seen by me till 1838. That 

 author's views so nearly coincided with mine, that it might 

 seem as if a communication of ideas had passed betwixt us ; 

 but, after allowing him due credit for his labours, I must still 

 continue to differ from him in a number of important points ; 

 yet, in order to avoid adding synonymous generic names, I 

 have revised my original terms, and in all cases where Presl's 

 character of his genera are conformable to my view, I have 

 adopted his names. 



It may be said that many genera have been created with 

 only trifling differences. But, when the technical characters 

 of several proximate genera of Ferns are compared with the 

 technical characters of a like number of genera belonging to 

 any other extensive natural family of plants, I may safely say, 

 that the genera of Ferns here given will be found to have as 

 good a right to rank as genera, as those of Graminece, Lili- 

 acecBf Orchide<B, LegunmioscB, &c. ; and Ferns, like these large 

 families, present very obvious distinctions on viewing species 

 of distant affinities; but, on taking a comprehensive view, a 

 gradual transition of form is seen to pervade through the 

 whole, not in a lineal, but in a complex, reticulated manner. 

 And, by making use of certain modifications of structure, 

 (which may be common to one or more species) I have been 

 enabled to classify them under what may be termed genera ; 

 and in the following arrangement, I will endeavour to show, 

 they are so connected with one another, that, in many 

 cases, it becomes very difficult to determine in which genus 

 the extreme or transition-species of groups should be placed, 

 thus proving, that in proportion as we become acquainted with 

 a great number of species, the more we find that " a genus 

 has seldom any real existence in nature as a positively deter- 

 mined group, and must rather be considered as a mere con- 



