PRESERVATION FOR THE HERBARIUM. 43 



the fructifications mature. V/e sliould rather, as a general 

 rule, advise their being gathered just as the masses of 

 spores reach their full gro^vth. If, however, more tlian a 

 single specimen of each kind is preserved, the perfectly 

 mature and the incipient states of fructification should 

 also be gathered ; but in the majority of cases the inter- 

 mediate state Avill afford the best materials for subsequent 

 examination and recognition. Certainly the fructification 

 is to be preferred in an early rather than a late stage of 

 development. 



Of course, when the species produces two or more kinds 

 of fronds, examples of each must be preserved, as, for 

 instance, in the Allosonis crisptts, the fertile fronds of 

 ^vhich alone would convey but a very indifferent notion 

 of the plant. The necessity of attending to this point is 

 even more strikingly apparent in such exotic genera as 

 the Strut/iiopteris, and almost all the species belonging to 

 the Acrostichum group. 



After being thoroughly dried under pressure, the speci- 

 mens, according to their size, should be arranged, singly if 

 large, or in groups resembling the natural tufts if suffi- 

 ciently small, on one side only of a series of sheets 

 (technically half-sheets, i.e. single leaves) of stout white 



