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of recuvva, spinulosa and multiflora, as they gradually uncoiled, and 

 by slow degrees developed their various divisions, but would long ago 

 have pronounced these species as different from each other, as any of 

 those which he had always acknowledged to be such. Recurva, 

 while expanding, may, by the unpractised eye, be passed as Pteris 

 aquilina, or as Polypodium robertianum, but never as either of those 

 species to which it has been so unnaturally united. 



A second barrier to the discovery of truth, is the imperfection of 

 the specimens selected for preservation. It has been an almost in- 

 variable rule to select convenient rather than characteristic specimens. 

 I use the modifying" almost," not because I have met with an exception, 

 but because my knowledge of herbaria is not so complete as to warrant 

 my saying the rule is invariable ; the full-grown, full-fruited, mature, 

 cheiracteristic fronds, are rejected as inconveniently large, except, in- 

 deed, in the rarer and smaller species, which being supposed valuable 

 in proportion to their magnitude, are generally selected by size ; thus 

 we invariably find the largest possible Lastraea rigida, and the smallest 

 possible Lastraea Filix-mas placed side by side, as the truthful repre- 

 sentatives of the respective species : the largest possible Allosorus cris- 

 pus, and the smallest possible Pteris aquilina always perform the same 

 office, and quite as unfaithfully. For the common species a mere fragment 

 is generally supposed sufficient. In the herbaria of Linneus and Smith, 

 the great authorities for reference, a bit nipped off" at random, fre- 

 quently suffices to exemplify a species. May I venture, as one who 

 has experienced the difficulty of drawing satisfactory conclusions 

 from such materials as these, to recommend an entirely new plan in 

 the preservation of ferns ? — that is, to select fronds, of whatever spe- 

 cies, of full size, of full developement, in full fructification, and perfect 

 from the very apex of the frond to the very base of the stipes ; and if 

 a portion of the rhizoma and root can be included, so much the better. 

 When the rhizoma is a running one, as in Thelypteris, its preservation 

 is indispensable. 



A third barrier is the disposition to preserve and value malforma- 

 tions and monstrosities, whether originating in blight, injury, or 

 other casualties. This taste prevails more generally than I could 

 have believed, had I not repeatedly been required to inspect as in- 

 estimable treasures, fronds with two tips, or deficient in the pinnae on 

 one side, or curled to the right hand or to the left. Far be it from me 

 to depreciate any fact, or class of facts, but this taste induces atten- 

 tion to matters that are totally at variance with the elucidation of 

 species. 



