THE MAKING OF AN HERBARIUM. ijj 



The plants should be mounted with their heavy stems as nearly 

 as possible parallel with the long diameter of the mounting sheet. 

 Two different species should never be mounted on the same sheet, nor 

 two plants collected at different times, although several plants col- 

 lected at one time may be so mounted. In the case of small plants, 

 it is well to mount several specimens on a sheet. When two large 

 plants are mounted together it is advisable to mount one with the root 

 turned toward the top of the page, which makes the bundles of 

 mounted plants of equal thickness throughout. Avoid crowding spec- 

 imens into the center of the sheet. Heavy parts should be placed 

 near the margins, but no part should be nearer than half an inch. 

 Care should be taken when mounting to have the best side of each 

 plant up. Ferns should, of course, be mounted with the sporangia 

 showing, and bell-shaped flowers with the inside of some of the corollas 

 visible. 



The practice of poisoning plants seems to be going out of favor, 

 and tight cases with close-fitting doors depended upon to keep the 

 plants from their insect foes. It is noteworthy that certain families 

 of plants, as the ferns, seem to have no charms for insects, while 

 others, as the composites, are apparently considered choice tid-bits. 

 If the plants are to be poisoned, this must be done before they are 

 mounted. The operation is a tedious one under any circumstances. 

 A pretty strong solution of corrosive sublimate is used, and the plants 

 are either dipped into it or it is sprayed upon them. They are then 

 laid between driers until the moisture has evaporated. The process 

 is said to frequently discolor the plants and the poison is most danger- 

 ous to handle, from which it seems probable that this method will 

 gradually be abandoned. With close cases it is possible to fumigate 

 the plants occasionally after they are mounted, with carbon bi- 

 sulphide, which effectually prevents insect depredations. 



It may be remarked in passing that too many collectors are en- 

 gaged in making extensive herbariums in which each species is repre- 

 sented by a single sheet. It is far better to have fewer species and 

 more specimens. Until one has brought together many representa- 

 tives of one species from different parts of the country, he cannot 

 know how much to allow for variation in his own plant. Indeed, two 

 localities near to each other will often show forms that are quite dif- 

 ferent in appearance. To the private individual, studying the plants 

 about him, the herbarium stocked with material that will throw light 

 upon the problems he encounters is the best for his purpose. A wise 

 collector will shape his collections to this end. 



