How to Prepare Herbarium Specimens

A. Pressing Herbarium Specimens

Pressing plant specimens is a relatively simple process. First, you will need a few supplies:

A plant press (available from a Herbarium supply company)
Newspaper
Cardboard cut to fit the plant press, with the fluted edges running the long way on the cardboard (this allows more air flow through the plant press and speeds the drying time)
Straps to tie the press together with
A small spade to get the plant out of the ground

When you have found a plant you wish to press, simply use the spade to extract the specimen from the ground. Include roots if possible (if these are too thick, they may be cut lengthwise). Place a piece of cardboard onto the plant press. Then, place the plant in the press between some newspaper on top of this piece of cardboard. Add another piece of cardboard above the specimen. Place the top part of the press onto this, and use your straps to tighten the press as much as possible. And voila - you have just pressed a plant!

If the plant specimen is too large to fit into the press, you may either cut out some of the middle section of the stem or fold the plant into a z-shaped pattern. Press sticky plants in between nonprinted newspaper in case the specimen becomes stuck to the newspaper. Leave the specimen in the press for about a week or until it is dry.

B. Mounting Herbarium Specimens

1. Pour a dollop of herbarium glue on a glass plate. Using the large brush, spread the glue evenly into a rectangular area.

2. Determine which side of the plant specimen should face up to display as many features as possible. Place the down side of the specimen on the glue and lightly press it down to get as much of the specimen covered with glue as possible.

3. Gently pull the specimen up from the glue and place it on the herbarium sheet. Place the specimen such that space is left on the bottom right for a herbarium label. If a herbarium label has already been made, mount this with the glue on the bottom right corner of the herbarium sheet.

4. Put a spot of glue under any loose pieces of the specimen and press them down. If the stem is thick, put a drop of cement glue across it and onto the paper on either side to help it stay down.

5. Pencil in the species and the collection number of the specimen in the lower right hand corner, so it can later be matched with its collection data if a label has not already been attached.

6. Lay the sheet upon two pieces of cardboard within the wooden pressing box. Cover with wax paper and two more sheets of cardboard.

7. Repeat the process (2-6) for as many specimens that you have. Add more glue and spread with brush as necessary.

8. On the top of the last piece of cardboard, place a thin wooden sheet and very heavy weights.

9. When finished mounting, wash glass plate with hot water to remove all glue.

One or Two Days Later:

1. Put the mounted specimen face up on a cardboard sheet. Lay weights on top of the glued specimen to press it onto the herbarium paper.

2. Place wood blocks on top of the edges of the herbarium sheet and lay down another piece of cardboard so another specimen may be laid down in the same manner.

A Few Days Later:

1. Remove each specimen and locate its collection data.
2. Enter the data into the working database.
3. Prepare an herbarium label for each specimen that does not already have one.
4. Glue on the herbarium label for each sheet.
5. Give each specimen a CS accession number:

a.) Use the number stamp to give the next unused number. If possible, place number in lower left hand corner. If this is not possible, find another visible place for it.
b.) Use the stamp that says "Colorado State University Herbarium" just above the number.
c.) Record in the accession number book the date, what numbers you used, where the specimens came from, and the name of the collector.

6. If it was requested, let the collector know that specimens have been mounted and entered in the herbarium and give them any information they requested (e.g. the accession numbers of the specimens).
7. Place specimens in the appropriate herbarium folder.