30 ON GENERA AND SPECIES. 



now being constituted of species separated from the well- 

 known genera Marattia, Angiopteris, Dancea, the technical 

 characters of which are, however, so slight that I do not 

 consider them worthy of adoption. 



Of Osmundaceae he describes twenty-four species, two of 

 which he characterises as a new genus under the name of 

 Leptopteris, but' which I consider not worthy of being 

 separated from Todea of Willdenow. 



Of Schizaeaceae he enumerates sixty-five species, arranged 

 under eight genera, three of which are new Lophidium, 

 consisting of five species separated from Schizc&a, and the 

 two others upon a single species each, founded upon doubt- 

 ful and even mistaken data, one of them (Spathopteris) 

 having no other authority than a figure of Plumier's 

 " Filices," which, in my " Genera Filicum," published in 

 1841, I show to consist of a barren and fertile frond of 

 two distinct Ferns. 



With regard to Lygodiaoeae he describes forty-one species, 

 thirty-nine of which belong to the genus Lygodium of 

 Swartz, and two to Hydroglossum of Willdenow. The 

 number of species of the three latter genera are also in 

 excess, Anemia alone having thirty-eight. 



In 1848, Dr. Presl published another work, entitled 

 " Hymenophyllaceae," in which he describes 185 species, 

 which had hitherto been comprehended under the well- 

 known genera Trichomanes and Hymenophyllum, but of 

 which Presl makes no less than nineteen genera ; and in 

 his " Epimelia Botanica " he characterises three more, 

 making twenty-two in all, about one-third of which are 

 founded upon a single species each. The data upon which 

 these genera are founded is derived chiefly from the size 

 and form of the cellular parenchyma, and the slight modi- 

 fications observable in the form of the indusium and 



