The guidance below will help you press your specimens, freeze them to successfully kill any bugs and then mount and label your pressed specimen ready for submission to the herbarium.
Every year the Society will aim to organise a herbarium day when specimens can be submitted and materials for mounting specimens are available to use.
Taking and pressing specimens
1) When selecting specimens take two cuttings, one to paint and the other to press. It is very important to make an accurate recording of that particular plant including the accession number – every plant at Eden has one. A note of the date is also important.
2) Ideally a press consists of two pieces of plywood with holes punched through, or a trellis of wooden strips lined with card. Webbing straps are needed to be able to close the press as tightly as possible. Failing this a good quality flower press can be purchased, or even a huge pile of heavy books !
3) Tie a label to the thickest stem of the plant with its accession number, your name and the date. Arrange it on a piece of very thin acid-free paper placed on top of a piece of blotting paper. Time should be taken to arrange it so that there is as much information as possible, e.g.:
a) Show upper and lower surfaces of leaves.
b) Snip off any forward-facing leaves or branches which obscure the flower and press these separately.
c) Arrange the flower to give maximum information – (both back & front views).
d) Bend longer plants to fit the page.
Place another piece of thin tissue paper over your arrangement and cover with a sheet of blotting paper and press as tightly as possible.
4) Twelve hours later, change the blotting paper. At this stage the specimen will still be soft enough to be gently re-arranged if you are not satisfied that it supplies enough information.
5) Change the blotting paper on days two and three. If your plant is particularly fleshy, you may have to change the blotting paper more often – protect thick stems with rolls of tissue.
6) Leave to dry completely. Care should be taken that the press is not kept in too hot an environment as it will make the plant go brown – use only gentle warmth.
7) Fruits should be gently dried and labelled clearly, put in a sealed bag or box.
Freezing of Herbarium specimens
Due to a previous infestation in the herbarium we are requesting that specimens are placed in the freezer, after they have been pressed and dried, but before they have been mounted.
1) Place them in an airtight plastic bag or container and freeze for between a minimum of 3hours and a maximum of 9 hours.
2 ) Remove them from the freezer and thaw at room temperature for 2 days, keeping them in the airtight bag/container.
3) Place them back in the freezer for a second chill time of between 3 to 9 hours.
4) Thaw at room temperature and mount the specimens after 2 days.
Mounting a pressed specimen
1) When it has dried, your specimen can be mounted on 16½” x 10½” archival quality,
2) It is vital that the plants are labelled correctly. The label should also be acid-free and
placed in the bottom right-hand corner. It should be typed with a laser printer.
Information to be included:
a) name of plant
b) accession number
d) name of collector
e) notes specific to the plant
f) where obtained
g) note on characteristics that could be lost in the pressing (colour, odour etc).
Stick the label to the card with a neutral pH adhesive.
3) If any fragments (seeds, fruits etc.) fall off, they can be kept in an acid-free paper
envelope. These should be kept as they can be used for analysis. Attach this to your card.
4) The specimen can then be fixed to the card. Place by the use of thin strips of linen-backed gummed tape, only moistened at each end. Linen thread should be used to sew the plant at intervals into place. Use one stitch with two knots at the back.
Always handle your specimen very carefully with flat hands on either side. Store in a dry atmosphere.