OF THE HERBARIUM-. 193 



Although by this arrangement the difficulty of getting at 

 the specimens is undoubtedly increased, still the advantages 

 are great, where (as I observed before) the fascicles are not 

 in constant requisition ; it saves the specimens from dust, it 

 keeps the wrappers in good order, and it helps to ward off 

 the ravages of insects. 



I referred just now to the need of selecting some system- 

 atic work as a guide in the arrangement of the herbarium 

 Ihis is easily done as regards the flowering plants and the 

 higher Cryptogamia ; there are works enough published to 

 satisfy the taste of every collector, whatever his views may 

 be, whether Limuean, Jussijean, Candollean or Lindleyan 

 But this, I regret to say, is far from being the case with the 

 lower Cryptogamia, the Lichens, Fungi, and %. Inde- 

 pendent^ of the fact that the systems hitherto arrived at 

 are far from perfect, there is the additional circumstance, that 

 science m its onward strides is ever bringing new species to 

 light, or compelling the re-arrangement of those with which 

 we are already acquainted. Consequently, we must either 

 hnd room in our catalogue for species of whose existence 

 we had no conception a short time before ; or, on the other 

 hand we must be prepared, in consequence of a deeper 

 insight having been gained into their structure and habits, 

 to separate species, hitherto closely combined, and not un- 

 frequently to place them in distinct genera 



To meet these difficulties a certain elasticity must be 

 allowed to the catalogue, so as to permit of the names of 

 species being introduced or removed without disturbing its 



Ionian arrang6ment - F f this P Ur P° se q™»rter-8heete of 

 foolscappaper are prepared ; one, two, or three for each genus 

 according to its size The generic name, with its reference 

 number, being placed at the head of the paper, the species 

 are added m due order beneath, a considerable'space being 

 left between each nameto admit of others being introduced 8 

 In this way new species can be inserted in °their proper 

 places, without having recourse to endless interpolSs 

 which disfigure the page and confuse the reader 



