Bulletin - United States National Museum - Smithsonian Institution

228 FLOEA OF WASHINGTON AND VICINITY.
sheet of glazed white paper which is ready at hand to receive it, and
iu the exact i)osition previously determined to be the best. Each specimen
should be first applied to the white sheet on trial for this purpose.
A dry cloth is then used to remove any excess of glue that may have
been spread on the paper, and to i)ress down any part of the plant that
is inclined to lie badly 5
the mounted sheet is laid down at one side, a few
sheets of jjaper (newspaper or brown pai^er) are laid upon it, and a board
(a press-board will do) is placed upon these. Another plant is then
mounted in the same manner, the board removed, the mounted plant
placed on the papers previously laid down, more papers put on this,
and the board restored. This process is repeated until all the plants
are mounted. The mounted sheets will be ready to place in the genus-
covers the next day. When the mounting is completed, the weight on
the pile should be increased.
The temporary labels should be kejit constantly with their plants.
Final labels should not be written until the i^lants have been mounted.
To economize time these should consist as far as i)0ssible of printed
blanks. In mounting, care must be taken to leave a sufficiently large
space at the lower right-hand corner for the label, and if, as often hap-
pens, more than one plant requiring separate labels go on the same sheet,
room for all the labels will have to be provided for prior to mounting.
The method of mounting with gummed strips, while it perhaps re-
quires more time and work, is in many respects a pleasanter one than
that with glue. In this case sheets of the same paper used for mount-
ing, or similar pajjer without lines, are gummed entire on one side with
mucilage. It is cheaper to make the mucilage from pure gum-arabic
by simjily soaking it in the proper amount of tepid water. To this,
however, it is much better to add a small quantity of glycerine, which
prevents, to a great extent, the tendency of the gummed sheets to roll
up at the edges on drying. To gum the sheets, lay them on a flat board
or other surface and fasten each corner with a pin gently driven through
the paper into the board (which should be of soft wood). It will be
found a great saving of trouble to have the board just a little narrower
and shorter than the sheet to be gummed, so that the mucilage can be
applied to the edges without danger of sticking to the board. A brush
similar to the one described for the glue is used to lay on the mucilage.
The latter should not be too thick, otherwise the coating will be un-
even, but at least two coats will be required to give it the proper adhe-
sive power. The second coat is put on after the first has become dry.
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