PREFACE. XI 



Hymenophyllaceoi (and other Ferns of Equinoctial Ame- 

 rica', in which six "new species" are described. The first 

 of these might have admitted of some doubt, as to its be- 

 ing really new, from the general nature of the specific cha- 

 racter, no less than from its being referred to Neurophyllum 

 of Presl ; but the mention of Hostmann's Surinam plants 

 removes every difficulty, and identifies the Fern in question 

 with Trichomanes Jlorihundum (H. B. K.) noticed at p. 

 129. Neither is it even a variety, like the remarkable var. 

 &. {I. c), which, in the absence of more materials at the 

 time, had once been deemed distinct (the T. Vittaria of 

 De Cand. and Hook, in Lond. Journ. of Bot. i. p. 137, t. 5). 



These statements are made from no invidious motive, 

 but simply to show that, without access to a most exten- 

 sive collection of specimens, from widely different locali- 

 ties, the best botanists, as has already been remarked, must 

 be liable to fall into mistakes of this kind, and therefore to 

 multiply the difficulties of the study, by loading the system 

 with dubious or wholly untenable species. It has become a 

 necessary, but in many respects an ungrateful task, thus to 

 confine the species, so far as practicable, within due bounds; 

 but this is one main object the author has kept before him. 

 His extensive herbarium has, however, necessarily pre- 

 sented many new forms ; and these, and other hitherto 

 unfigured ones, he has been anxious, wherever it could be 

 done, to illustrate by faithful representations, executed on 



