USE OF THE END PIECE OF PRESS
While pressing use the plywood press end to hold down the pile and keep it orderly. Move the board up as needed. This leaves both hands free. It is also a good cutting surface in fancy hotels when you need to section fruits or thick stems.
ORDER OF SHEETS WHILE PRESSING
If you do not write the field notes as you are pressing plants, reverse every other collection (consisting of one or more duplicates). Then it will not be necessary to open every sheet when you are counting them, writing up the field notes, and writing the numbers on the sheets. Always keep the upper surface of the specimen up.
It is very helpful if the collector's initials are placed by the number, i.e., A.G. 45038. If labels are lost, or collections mixed up, it is much easier to recapture the missing data or return the specimen to its proper place. This saves time if you are collecting or processing your plants together with someone else using the same number range, aids in replacing lost labels, and saves confusion if several collections are shipped together. Put the number in the same place on the newspaper each time, preferably along one edge. It is much easier to sort them.
After the sheets are numbered, put all or half of the bundle with the folds in the same direction. Do not flip half of the bundle upside down to balance the packet--this just makes it more complicated to process the plants later.
Make each specimen for any given number as complete as possible. If both flowers and fruits (or different leaf shapes, etc.) are available, each sheet or set should be representative. After drying, combine parts that were dried separately to form complete specimens before packaging and shipping.
SIZE CONSTRANTS ON SPECIMENS
Make the specimens shorter than the mounting paper! More damage is done if they must be refolded later and any parts which extend beyond the newspaper will break off and be lost. Always keep in mind what the material will look like once it is a mounted specimen, not merely getting the plant into the newspaper any which way. Mounting paper at MO is 29 cm (11 1/2 inches) wide by 42 cm (16 1/2 inches) long.
When wilting is a problem, collect for awhile, then press in a convenient spot, then collect again, etc. Wilting can be reduced by sprinkling the bags with water and keeping them in the shade, or placing wet newspaper or towels inside the bags; but remember the sun shifts. If available, white opaque plastic bags do not produce as great a green-house effect. Back at the base camp, wilting can be reduced by putting the bags in an air-conditioned room or in a refrigerator if available, but seal them because the chilled air is often dryer.
Except for vines, slightly break stems and fold them into a "V" or "N" rather than curve them:
If plants are small, put several on the sheet to fill it up:
Balance the quality of individual plants on each sheet, some nice, some poor (if not all in prime shape). Otherwise you may end up with the poorest sheet for your own institution. It simplifies later processing if the collector designates the chosen home institution sheet.
Grasses and other herbs should not be "top-snatched." Always collect the full specimen, roots and all; dig deep enough to find rhizomes or other underground parts if they are present. Be certain to remove the soil from the roots by shaking or washing.
It is best to arrange plants for pressing with the same surface facing upwards as will be seen once the specimen is mounted. Always keep that side up during pressing, numbering, drying, and sorting.
Arrange plants before drying to clearly show both surfaces of leaves and reproductive structures, paying particular attention to ferns. Press some flowers open, and some closed, and others split to show the internal structures (especially in Polemoniaceae and monocots). Phyllaries (bracts) in the capitula of Asteraceae are very important, and should be pressed so some can be clearly seen. Pubescence, stomata, and other characters are frequently more important on lower leaf surfaces than upper. If only one large leaf or fern frond sample is available, it should be folded so part of both surfaces can be seen.
Do not cover flowers, fruits, or stems with leaves; either spread the leaves away from the other plant parts, or fold the leaf underneath them. When folding leaves, keep the larger part underneath so that you can still measure length, width, etc.:
Cut or break off excess leaves, but always keep part of the petiole to show the position:
Never cut off the petiole base and the stem attachment of a compound leaf. If possible, keep some of the petiole bases of the other leaves and the apex of the stem. Do not mistake a large compound leaf for a branch with simple leaves. Do not split the twig, because the opposite or alternate arrangement of the leaf will no longer be evident. A specimen of two sheets or more may be necessary with very large leaves.