17 



of life, let us assume that our herbarium begins at the ferns 

 and extends through all the families of flowering plants to 

 the highest, the composites. In order to know where to find 

 each family in this vast host, an index is necessary. For this 

 purpose the families are numbered in sequence, beginning with 

 the ferns. An alphabetical list is then made, in which the 

 name of each family is followed by its number in the 

 sequence. A glance at this list will at once tell us where to 

 look for the required family. Having found this, we must 

 have another index, for just as the families follow a sequence 

 of relationship, so do genera and species. By arranging and 

 numbering the genera in sequence and making a list similar to 

 the first, the difficulties in finding the genera are overcome. 

 The species must still be disposed of. In small genera we 

 may be able to get along without indexes, but with the large 

 genera which often contain more than a hundred species it is 

 better to arrange the species in their natural sequence, in this 

 following the latest monographs of the genera, and providing 

 an alphabetical index also. 



For locating the families and genera in the cases, several 

 devices are employed. In some herbariums a piece of paste- 

 board the size of the mounting sheet with a smaller piece of 

 the same width hinged to one of its ends is used. The large 

 piece is laid in the pigeon hole at the beginning of a family 

 and the smaller piece, hanging down in front, has the family 

 and list of genera which it contains, printed upon it. This, 

 however, is a downright nuisance, for the hanging cardboard 

 is always in the way. Another way is to label the pigeon 

 holes by printed slips which are held in place by a contrivance 

 fastened to the partitions, but this is objectionable because 

 there is then no place for an index and because the labels have 

 to be changed every time there is an addition of new material. 

 Perhaps the best way yet devised, is to make use of a piece 

 of light wood the size of the mounting sheet and about three- 

 eighths of an inch thick. This is laid in the pigeon hole at 

 the beginning of each family. On the visible end is printed 

 the name of the family and its number. The upper surface 

 of such a marker gives ample room for a catalogue of all the 



