[31] DIRECTIONS FOR COLLECTING PLANTS KNOWLTON. 



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 afc 

 completeness, but simply to supply a foreign demand and serve as ai 

 means of increasing and enriching his herbarium proper. As this ap.- 

 proaches completion, therefore, the other is reduced in volume. 



In putting away the fully dried plants they are accordingly dividedl 

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

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

 lected, which should only be done where the plant is in demand, all but . 

 one, of course, are relegated to the duplicate department, and usually 

 without further ceremony. Specimens selected for the herbarium, how- 

 ever, require still another form of treatment. They must be poisoned, . 

 Let no one think that this can be dispensed with. As certain as that it 

 requires the proper cycle of seasons for it to grow, so certain will the 

 time come when if left unpoisoned it will be devoured by the insect pests ■ 

 of the herbarium. Neither have much confidence that this can be 

 done after mounting, and thus waste neat and costly glazed paper by 

 mounting them first. The insects naturally work on the under side of the 

 plant, where the poison can not be applied after it is down. The labor of 

 poisoning is, perhaps, the least pleasant of all kinds of herbarium work, 

 but its absolute necessity should at once dispel all hopes of evading it. 



There is an almost complete uniformity among all botanists as to the 

 kind of poison to be used, the accepted substance consisting of corro- 

 sive sublimate and alcohol, the proportion being one ounce of the for- 

 mer dissolved in one quart of the latter diluted 25 per cent. The mode 

 of applying it varies considerably. The use of the camel's hair brush 

 is slow and tedious, but consumes the least poison, and may be de- 

 fended on economical grounds, though not likely to be as thorough as 

 other methods. Probably the best way, all things considered, is first 

 to fill a trough or large platter with the poison and then dip the entire 

 plants in the liquid, handling them with tweezers, and letting them drip 

 before laying them aside. After poisoning, they should be immediately 

 placed in dry papers ; otherwise all the pains taken to press them 

 nicely will be in vain, and their colors will vanish after all. This can 

 be prevented by care, and once changing will be sufficient. It is not 

 necessary to use regular driers for this purpose — newspaper is good 

 enough j and it will be found very salutary to use, for drying out the 

 l)oison, sheets of paper designed for the duplicate department or for 

 general use. The habit of the insects is to bore through the sheets on 

 which the plants are laid. They never go round the ends of them, but 

 eat circular tubes downward or upward through the paper until they 

 find a suitable habitat. If all the papers in the herbarium are saturated 

 with the poison, they find themselves greatly restricted in their opera- 

 tions, and as it is not usually deemed worth while to poison duplicates, 

 it is a great protection to them to have them in poisoned papers. The 

 temporary label should be kept with the phmt throughout the poisoning 

 ,as throughout every other process, 



