188 OF THE HERBARIUM. 



material from different localities, embracing widely-sepa- 

 rated areas. 



The more numerous the localities represented in an her- 

 barium are, the more valuable is it in the eyes of the man 

 of science. For the same reason he should bring together, 

 in the case of the Phanerogamia, not only flowers, but ripe 

 fruit, both with and without the capsule, or, if the plants are 

 dioecious, examples of both the sexes ; in the case of the. 

 Cryptogamia, sterile as well as fertile forms from numerous 

 localities, since, in many cases (as for instance among the 

 Mosses) peculiarities of situation, hindering or promoting 

 the fertility of a plant, influence its habit and character in 

 no slight degree. In a word, in each order of plants, the 

 collector should endeavour to obtain the successive stages 

 of development, if he intends to study them thoroughly, and 

 to give a scientific value to his collection. 



That he may study the specimens with ease, his herba- 

 rium should be so arranged, that he may be able to lay his 

 hand at any moment, and without loss of time, on the ex- 

 ample he wishes for ; and also be able to take it out and 

 replace it without injury to the collection. 



For this, I recommend the following plan. The wrappers 

 being laid on a table with their openings looking to the 

 left, the whole of the species belonging to a single genus 

 (or a section of them, if the genus is very large) is to be 

 lifted -off the pile, and enclosed in a separate wrapper, the 

 opening of which looks to the right. This arrangement 

 tends greatly to convenience in handling the specimens, as 

 the operator can remove each genus, (or, it may be, portion 

 of a genus,) ■with the greatest ease, and, when properly 

 labelled, any desired genus can be got at without disturbing 

 the other packets. 



The genera included under an order should next be 

 isolated. As a rule, this involves a pile of specimens much 

 too bulky to be comprehended within the limits of a single 

 wrapper. The better plan, therefore, is to lay the pile be- 

 tween two sheets of stout pasteboard of corresponding size, 



