FLORA OF WASHINGTON AND VICINITY. 223 



After the plants have hiin a week without pressure and become thor- 

 oughly dry, they may be taken out of the driers and thin papers and 

 jjlaced in the herbarium. They are usually first transferred to rough 

 paper of some kind, either double and placed between the folds, or, as 

 I prefer, single, and simply laid on with their labels. System is useful 

 in all things, and many valuable specimens will be saved by observing 

 certain rules even in such simj)le matters as this. The papers upon 

 which the specimens are placed should be ample, say 18 hj 1-5, or 

 at least 17 by 11 inches, and should be of uniform size. Many such 

 papers will be in constant use in the herbarium, and a reserve package 

 should be kept on hand. They need not generallj^ be bought, as noth- 

 ing is better than common newspapers, especially if the jiaper is moder- 

 atelj' strong and heavy, and nearly everj' one has a surplus of these ; 

 but it is well "worth while to cut thehi to a measure. In laying off the 

 plants the thin papers should be systematically restored to their general 

 package without having to move them twice, and the driers released for 

 further use. Only one or two driers will be needed for each speci- 

 men after the last change, when they are laid away to dry out. It will 

 often happen that there are several specimens of the same plant. Of 

 course only one label is written for these, and, therefore, they must be 

 kept together throughout. This will be secured if the plants are changed 

 in the systematic manner described above ; but the label will sometimes 

 be found on the upper and sometimes on the under specimen when they 

 finally come out from the press. In putting them away it is, of course, 

 best in such cases to have the upper specimen contain the label. 



A botanist's collection always consists of two departments: the herba- 

 rium proper and his duplicates. The former he arranges in strict botani- 

 cal order, sees to it that it contains a perfect specimen fully represented 

 of every plant he has ever collected, and adds to it as many other plants 

 as he is able to obtain through the process of exchanging, or in any 

 other way. The latter contains a large number of specimens of each of 

 the rarer plants of his local flora, and eventually he will add to it other 

 rare plants obtained from other sources. It does not aim at com- 

 pleteness, but simply to supply a foreign demand and serve as a means 

 of increasing and enriching his herbarium proper. As this approaches 

 completion, therefore, the other is reduced in volume. 



In putting away the fully dried plants they are accordingly divided 

 into these two classes, a part going into the herbarium and a part to 

 the duplicates. Where several specimens of the same plant are col- 



