Pressing Plants

Pressing Plants

The Linnean Society of London is home to an extensive herbarium, which is a collection of plant specimens preserved for the purposes of identification, research and education. These collections are crucial for ongoing research on plant biodiversity.

In order for a herbarium specimen to be of use to a researcher, it needs to be displayed in such a way that all of the plant’s key structural parts can be seen and studied.

Things you might need:

Tape measure
Heavy flat object (heavy books or bricks on top of card)
Paper card
Blotting paper or other absorbent paper (newspaper is fine)
PVA glue or fine tape
A4 paper

Activity details:

Age: 8+
Difficulty: Medium
Preparation time: 1 hour
Running time: ~ 3 days

Learning points:

Field skills
What species live around your home
How to keep good records

How to press plants:

  1. In dry weather, collect a whole plant, including the root system; one which is healthy, has average-sized leaves and flowers, and which is no bigger than an A4 sheet of paper.
  2. Record the following: the date the plant was collected, the location it was found, the dimensions of the plant, and its colour, using a colour chart, like the one made by James Sowerby (lower image).
  3. Remove any excess soil attached to the specimen and place it on top of blotting paper that has been laid on top of a solid flat surface. In the following order, place on top of the plant another piece of blotting paper, one sheet of stiff card (corrugated or other), and then a heavy object such as a book or brick.
  4. Ensure that pressing occurs in a warm, dry and well ventilated room. Check on the plant every 24 hours. The drying process can take from 3 days up to 3 weeks depending on the specimen.
  5. Once dry, attach the plant to an A4 sheet of paper by sparingly using PVA glue and tape. Write the information recorded when the specimen was collected onto the paper on which the plant has been mounted. Finally, title the herbarium specimen with its species name.
Pressing plant

How to take the investigation further...

Once you have produced several herbarium sheets and researched their classifications, you can begin to group them in folders according to their genus, family or other classification.