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place, so as to satisfy rule 3, and if not sufficiently representa- 

 tive, supplement bj material from other parts of the plant, noting 

 carefully their connection. 



III. The Peeparation and Preservatiojs" of Specimens. 



SjDccimens should be so preserved that their distinctive char- 

 acters may be retained and that tlie minute structure of the flowers 

 and other organs can be subsequently examined. The immediate 

 object is to preserve them from tlie attacks of fungi (moulds) 

 and insects with a minimum of injury to the general structure 

 of the plant. Preservation may be effected by either the dry 

 or wet methods, or by a combination of both. 



A. The dry method. — Plants may be dried in various ways, 



but for our present pur])oses only methods of drying under pres- 

 sure between absorbent paper and of drying in the air need be 

 described. The former is most generally employed for 

 '' exsiccata '' or herbarium specimens, as usually understood, as 

 it has the immediate advantage of reducing the bulk of the 

 specimens to a minimum, of preventing their curling or excessive 

 shrinking and generally of fixing them in such a position as to 

 exhibit all their parts in their natural connection. Drying under 

 pressure, however, is not applicable to all specimens, either 

 because they are woody and not compressible, too succulent, or 

 again so^ delicate that they would be liable to be crushed out of 

 recognition. Of such specimens some must be air-dried, whilst 

 others can only be preserved in fluids. Turther, it frequently 

 happens that only certain parts are suitable for drying under 

 pressure, and in such cases the pressed material will have to 

 be supplemented by material dried in the air or preserved in 

 fluids. Then, again, specimens which in the first instance had 

 to be preserved in spirit may subsequently be dried under 

 pressure. 



Drying under pressure. 



The chief points which must be 

 the drying of plants under pressure between absorbent paper are 

 (1) the kind of paper and the mode of pressure, (2) the nature 

 of the specimens, and (3) the conditions arising out of the 



ultimate destination of the specimens, that is their deposition in 

 a herbarium. 



The Paper. — Drying of specimens must be effected quicklv 

 and sufficiently completely to prevent decomposition, tie de"- 

 velopment of moulds and the ravages of insects. The absorbent 

 jxiper must be non-sized and soft enough to apply fairly 

 closely to the specimens, but also sufficientlv strong not to dis- 

 integrate when impregnated with the moisture taken up. Nor 

 must it be so bibulous as to draw moisture freely from the air. 

 Many kinds of packing papers, old newspapers and most blotting 

 papers will answer as substitutes for those which are eometimes 

 manufactured es])ecially for drying plants. A few drops of water 

 sprinkled over the paper will, by the readiness with which they 

 are absorbed, show whether or not the paper is suitable for drying 



