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The work by which Presl first attained his reputation was published 

 at Prague in 1836, under the well known title of ' Tentamen Pterido- 

 graphiae.' He there divides the ferns into five orders : — Filicacea?, 

 Hymenophyllacese, Marattiaceae, Osmundaceae and OphioglossaccEe ; 

 of these the FilicaceaB alone are analyzed, the Hymenophyllacege be- 

 ing announced as the subjects of a future memoir, while the remaining 

 orders are left for other botanists to elaborate. " Should it please Al- 

 mighty God the Hymenophyllaceae shall be discussed in a separate 

 memoir: but 1 purpose leaving the remaining orders to the skilful 

 hands of other historians." The memoir thus promised in 1836, was 

 completed in 1842 ; and we consider it so excellent, that we trust no 

 apology is necessary for giving verhatim a large portion of its contents. 



Comparing this treatise with that upon the Filicaceae, it is deci- 

 dedly superior. In the earlier work there are combinations, both as 

 sections, genera and subgenera, which will not bear the test of critical 

 examination : but in the present work the groups are described with 

 the utmost care, and perhaps are indebted for some portion of their 

 greater value to the fact that they depend almost solely on the fructi- 

 fication. Presl was the first to systematize the venation of ferns, and 

 carried away by the beauty, the novelty, and indeed by the intrinsic 

 utility of this guide, he perhaps, in some instances, gave it too great 

 an importance, and allowed it to take precedence of the characters of 

 fructification. In the Hymenophyllaceae he finds the venation more 

 uniform, and is therefore driven back on the fructification; and the 

 result of the application of his great analytical powers to so safe and 

 certain a guide, is the institution of genera more definite and tangible 

 than any previously promulged in any section of the filicoid plants. 



We have already seen that the author considers the Hymenophyl- 

 laceae a group as distinct from the other annulate ferns as are the 

 Osmundaceae. To this opinion we are scarcely prepared to subscribe. 

 The capsule in these plants possesses a most distinct articulated ring, 

 as in the true Polypodies : yet generally differs in being attached to 

 the receptacle by a portion of its diameter, the ring not unfrequently 

 passing transversely round the capsule, like a belt ; whereas, in the 

 Filicaceae of Presl, it is almost invariably stipitate, its stipes generally 

 appearing continuous with the ring. The receptacle in the Hymeno- 

 phyllaceae is free ; while in the Filicaceae it is almost invariably im- 

 bedded. And here it may be as well to observe, that every part of 

 the vein in ferns seems liable to become a receptacle by the presence 

 of capsules. In the Fihcaceae we find a distinct and apparently in- 

 dependent involucre ; it does not appear to us to be the cuticle of the 



