24 A FLORA OF MANILA 
THE HERBARIUM 
A collection of dried plants is called an herbarium, and such a collection 
is most essential in the study of taxonomy or systematic botany. 
For convenience in referring to specimens, the dried plants are com- 
monly mounted on sheets of fairly stiff white paper, the usual size, known 
as the standard herbarium sheet, being 29 by 42 cm. Any paper of good 
quality and fairly stiff can be used, but about 60- bi ae linen ledger paper 
is best adapted to all purposes. 
There are several methods of mounting specimens, the chief being a 
combination of gumming and strapping, or strapping alone. Ordinary glue, 
fish-glue, or mucilage, can be used in fastening specimens to the herbarium 
sheets, but the most satisfactory adhesive is gum arabic dissolved in cold 
water to the consistency of ordinary mucilage; to this mixture a small 
amount of carbolic acid should be added to keep it from souring. The 
form of gum arabic known as powdered acacia is the most convenient for 
general use, as it dissolves very quickly. 
With gum arabic solution one can make his own gummed paper, for 
strapping plants, by taking any tough white paper and with a soft brush 
painting over one side with the gum arabic solution and allowing it to 
dry. It can then be cut into strips of various widths and used as desired. 
In gumming plants a thin layer of the gum is spread out on a smooth 
hard surface by means of a brush. The plant to be mounted is then placed 
‘on this gummed surface and all parts are gently pressed down so that the 
gum is evenly distributed over the lower surface of the specimen; it is 
then carefully removed and transferred to the mounting paper in the 
position desired and the sheet placed between driers under light pressure 
until thoroughly dry. Later the heavier parts, such as the stems, ends of 
leaves, etc., are more firmly fastened by the use of narrow strips of 
gummed paper. This method is the best one for a collection that is to be 
consulted or studied a great deal. 
Another general method is to lay the plant on the mounting paper in 
the position desired and firmly fasten it in place by the use of strips of 
gummed paper, without previously fastening the plant to the paper by 
gumming as described above. The advantage of this method is that the 
entire plant can, if necessary, be removed for purposes of study, which 
is impracticable when the specimens are gummed. Plants can be mounted ~ 
without the use of gum by folding strips of paper about the stems and 
other coarse parts, and pinning the ends of -the paper strips to the 
herbarium sheet. 
In mounting specimens the leaves should be so arranged that both 
surfaces are shown. Detached flowers, fruits, small leaves, etc., are best 
preserved by placing them in small envelopes or packets which are attached 
to the sheet. Mosses, scale-mosses, most fungi, lichens, etc., can be pre- 
served in packets which should be attached to herbarium sheets. Only one 
species should be mounted on a single sheet, but several specimens of the 
same species showing variation etc., can be attached to the same sheet. 
The name of the plant, genus and species, locality, collector, and date 
of collection should be written on the lower right-hand corner of the sheet, 
or on a label attached to the sheet; sometimes other data are added but 
these additional data are best preserved on the field label which may be 
attached to either the- upper or lower left-hand corner of the sheet. 
Herbarium labels are usually about 6 by 12 em, and should be printed on 
paper of good quality. 
