[37] DIRECTIONS FOR COLLECTING PLANTS KNOWLTON. 



down to the sheet. This is best done by a pressure of the thumb-nails 

 along both ends of the strip towards and closely up to the plant. 



As to the relative merits of the two modes of mounting, it may be 

 said that perhaps for very large herbariums, which are in constant use, 

 the method with glue is the best, since the tenderer parts of the plants 

 are thus firmly held to the sheets, and not liable to be damaged. This 

 method, however, is not sufficient in cases of terete stems, and needs 

 to be supplemented by strips over such parts. The objection to the 

 strip method is that it conceals some parts of the plants and makes the 

 sheets look less natural. But, if carefully and tastefully done, this 

 objection need not have great weight. On the other hand, it has this 

 important scientific advantage, that if mistakes are made the plants 

 may betaken off, and if very essential they may be removed uninjured, 

 turned over, or studied. With many botanists these considerations 

 preponderate largely, and it is probable that they come to have more 

 and more weight as experience points out the defects of the glue sys- 

 tem. For small or private herbariums, therefore, the strip system is, I 

 think, upon the whole, to be preferred. 



In mounting plants, by whatever method, a few precautions will be 

 necessary. The majority of specimens are small enough to admit of 

 putting two or more on a sheet. Unless very small, no two from the 

 same locality should be mounted together, except where they differ in 

 some important respect, which it is desired to show. But a sheet is 

 vastly improved where specimens of the same plant, from widely vary- 

 ing localities, are grouped together upon it. In the course of a botanist's 

 travels and exchanges, he will obtain duplicates of this kind. Some seem 

 to have an idea that if they have a plant, no matter from what source, 

 this is sufficient; but an herbarium consisting of only one specimen of 

 each species would be next to valueless, though it should thus embrace a 

 large part of the flora of the country or the globe. Instead of putting 

 everything into the duplicates of which you happen to have a representa- 

 tive, it should first be ascertained whether a new plant is from a different 

 locality from that of any you already have mounted; if so, mount it at 

 all events, and if possible on the same sheet. The first specimen mounted 

 on a sheet ought to go on the right-hand side, so that its label will nat- 

 urally occupy the lower right-hand corner. Without crowding it out 

 too near the margin, care should be taken not to waste space by putting 

 it too near the middle so as to prevent another specimen from being 

 mounted on the left of it. If lacking in any of the particulars which 

 should be represented, and can be obtained trom the local flora, such as 

 fruit or radical leaves, these should be procured and added to the sheet 

 before specimens from other localities are given a place. The date, etc., 

 of collecting these additional parts should be added to the label, or, if 

 they seem to require it, a new label may be written for them. Where 

 only two specimens fill a sheet, one of the labels should occupy the 

 right and the other the left corner; if three go on, the third label may 



