Bulletin - United States National Museum - Smithsonian Institution

222 FLORA OF WASHINGTON AND VICINITY. •
losing plants and having them turn up in an injured condition among
the wet papers.
The differences in the nature of plants will render some additional
precautions sometimes necessary. It is often well after the first chang-
ing to group into one place all the thick-stemmed specimens and give
them more driers, or to group all the grasses, rushes, etc., by themselves,
give them fewer driers, and perhaps change them less often. Some
kinds of plants can with diflBculty be pressed at all, and must be for the
most part dried out between papers with scarcely any pressure. This
is the best way with Opuntia, Sedum, Portulaea, etc. Others, like
Cynthia Dandelion, are so full of juice that very light pressure seems to
disintegrate the structure and turn the specimens blaclv. There are a
few plants, such as Gerardia^ Buchnera, Herpestis, and Bapfina, which
are said by the books to "turn black in drying," as though this would
occur whatever plan might be adopted. To some extent this is true,
and yet by the above method I have dried all these plants so that the
green color largely predominates in the dried specimen.
I cannot advise the purchase of patent kinds of drying paper. I have
tried the best of them, and, independently of cost, I prefer the straw
paper. I have also heard other experienced botanists make the same
admission. Simplicity and convenience are important objects to aim at,
and for most botanists economy is equally so.
The drying of damp papers is always considerable trouble, and various
devices for hanging them up on frames or "horses" built for the pur-
pose hav^e been used. These are well, but beginners will scarcely have
them, and must resort to other methods. If you have a lawn, and the
weather is fine, it is best to spread them out in the sun, where they will
dry immediately. The thin brown papers here recommended dry much
quicker than the thicker kinds sold, and if the pains are taken to open
them entirely out, the process is still further hastened. If you have
only in-door facilities, the papers may be spread out over the tables,
chairs, and floor, where they will usually dry in a night or a day. It is
a good plan to heat them in an oven after picking them up and before
using. In throwing them down they will dry faster if no effort is made
to lay them in any systematic way, and no evils need be feared from
their becoming rolled up and wrinkled, as this only increases the sur-
face for the access of the air. They should, however, be picked up systematically,
keeping the ends even ; otherwise, they will consume much
time when needed for rapid use, where thej^ must often be picked up
with one hand while the other is doing something else.