The herbarium holds sixty thousand specimens, and about four hundred are added each year. Ferns are among the easiest to press well, which is why new volunteers start with them.
A frond is cut with its label already written, laid flat between sheets of newspaper and blotting card, and pressed in a wooden frame with straps. The papers are changed daily for a week.
Mounting
Once dry, the specimen is fixed to acid-free card with linen tape and a little glue, and given a label with its name, where it grew, when and by whom. Kept dry and dark, it will last centuries.
The label matters more than the plant. Without it, a specimen is just a pretty leaf.