PRESERVATION OF AN HERBARIUM. 385 



After all we can do, plants dry very variously. 

 The blue colours of their flowers generally fade, nor 

 are reds always permanent. Yellows are much more 

 so, but very few white flowers retain their natural 

 aspect. The Snowdrop and Farnassia, if well dried, 

 continue white. Some greens are much more perma- 

 nent than others ; for there are some natural families 

 whose leaves as well as flowers turn almost black by 

 drying, as Melampyrum, JSartsia, and their allies, 

 several Willows, and most of the Orchidea. The 

 Heaths and Firs in general cast off their leaves between 

 papers, which appears to be an effort of the living 

 principle, for it is prevented by immersion of the fresh 

 specimen in boiling water. Nandina domestica, a 

 Japanese shrub, lately introduced among us by Lady 

 A. Hume and Mr. Evans of Stepney, is very remark- 

 able in this respect. Every leaflet of its very compound 

 leaves separates from its stalk in drying, and even 

 those stalks all fall to pieces at their joints. 



Dried specimens are best preserved by being fast- 

 ened, with weak carpenter's glue, to paper, so that 

 they may be turned over without damage. Thick and 

 heavy stalks require the additional support of a few 

 transverse strips of paper, to bind them more firmly 

 down. A half sheet of a convenient folio size, should 

 be allotted to each species, and all the species of a 

 genus may be placed in one or more whole sheets. 

 On the latter the name of the genus should externally 

 be written, while the name of every species, with its 



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