Pressed: The Herbarium

17 Sep

So far it is going well here at the Garden and for my first week with the Science Department. This week I am working with the Herbarium. Though the word herbarium may elicit blank stares and yawns, they play a vital role for not only botanic gardens, but for the future of our environment.

A herbarium is a collection of preserved plants. The majority of plant material go through a process of pressing and drying, but bottling in a preservative (most likely alcohol) is also done. Herbariums play an important role in botanic gardens, but they are usually closed to the public and are hidden away from the elements. Like a library, herbariums keep a thorough record of specimens and depending on the institution they will have wild collected specimens or cultivated specimens. Generally botanic gardens and botany departments of universities will only collect pure species plant, while public gardens will collect important hybrid and cultivars. With these pressed specimens you can check the vitality and abundance of a species in the wild, the shifting range of a species, or a change in time of the life cycle of a species. These pressed specimens can also provide precious DNA for sequencing, identify forgotten plants, and keep a record of our botanic history. Herbariums, specifically horticultural ones, can end disputes if one plant breeder has introduced a preexisting plant hybrid/cultivar under a different, or help record/identify heirloom plants that once existed (and were found again).

The herbarium here in Wisley doesn’t go out to collect wild specimens, but they accession plants that were and sent in. Their mainly collect and record new hybrids/cultivars important to horticulture and all the plants that are and have been growing at Wisley. (There was a 100 year period when Wisley lost funding, so no herbarium was keeping track of the plants.) So my first job for the past to days was two collect crabapples to press.

The herbarium manager gave me a nice counter top to work on.

The herbarium manager gave me a nice counter top to work on.

The herbarium manager created a list of crabapples of interest that needed collecting. He take me out and showed me the ropes yesterday and today I was mainly on my own. I collected and pressed four specimens today and tomorrow I will probably start on ornamental pears.

Here is my little baggie of collected specimens.

Here is my little baggie of collected specimens.

After collecting I sort through one specimen at a time, so that way there is a very low chance of a mix-up.

My first crabapple of the day.

My first crabapple of the day.

When righting a short description, you try yo include details that cannot be gathered just by looking at the specimens. For example: tree shape, size, fragrance, if the fruit are distributed in a certain way, etc. This also includes color. Color from a fresh specimen and a dried specimen are quite different, so indicating the color with a standardized color chart can help the researcher envision how the specimen may have looked like fresh.

A standardized color chart adds to make the description, well, more descriptive.

A standardized color chart adds to make the description, well, more descriptive.

After writing a description, ‘colorizing’, and checking the name one last time, I prepare the specimens for pressing. First I lay out the boards, cardboard, blotting paper, and foam (if needed). The protective boards are laid first, since they will help spread the pressure evenly and protect the pressing specimen. Next corrugated cardboard, then foam if the specimen is chunky, and blotting paper on top.

Everything is laid out in the right order and the little specimen is ready to be pressed.

Everything is laid out in the right order and the little specimen is ready to be pressed.

Once that is ready I lay the specimen out and play around with the orientation before I commit to pressing. First I gently lay the blotting paper on top of the specimen while adjusting the leaves and applying firm pressure. Then lay everything else on top while still applying firm pressure.

Adjusting while placing the final layers on top is a bit tricky, but with practice it becomes less daunting.

Adjusting while placing the final layers on top is a bit tricky, but with practice it becomes less daunting.

When the ‘sandwich’ is successfully stacked and held, straps are brought in to help tightly cinch everything together.

Once the straps are secure you can breathe a sigh of relief.

Once the straps are secure you can breathe a sigh of relief.

To make the pressure even greater, long wood boards are slipped under and turned on their side to increase tautness on the straps.

Herbarium pressing is all about (quick) even pressure.

Herbarium pressing is all about (quick) even pressure.

Once done, everything is placed in the drier to sit until they are completely dried and ready to mount.

Not all herbariums have a drier, but it really helps with  preserving the colors and warding off mold.

Not all herbariums have a drier, but it really helps with preserving the colors and warding off mold.

Since moisture is the enemy of herbarium specimens, pressing large juicy fruit got a bit tricky. To help large round fruit press better, we sliced them in half with the intact side up or if they were really large we sectioned them in a few different ways to give an idea of what the full fruit would have looked like.

This crabapple was almost the size of an eating apple.

This crabapple was almost the size of an eating apple.

Sometimes you never know what you are doing to find inside:

This crabapple naturally has red flesh, hence the name Malus x heterophylla 'Redflesh'.

This crabapple naturally has red flesh, hence the name Malus x heterophylla ‘Redflesh’.

Hopefully, I will get to mount some previously pressed specimens this week, but until then I will still be happy playing around with the press.

Adjusting the final arrangement to make sure nothing is touching or overlapping.

Adjusting the final arrangement to make sure nothing is touching or overlapping.

That’s it for now, but check back tomorrow or the day after for my post on two gardens I got to visit last weekend. See you soon!

FOLLOW-UP:

Sept. 29th
Sorry, I know I am a bit late for adding this, but it wouldn’t have been right if I left it out. While I waited for my collected specimens to dry, I was given some pre-pressed specimens to mount. There is a bit of finesse to mounting specimens and some people really make it an art form. The key to a good mounted specimen is making sure all the loose bits are secure, it’s flat, and as many different parts of the plant is represented on one sheet.

Here is the mounting table with all my tools lined up.

Here is the mounting table with all my tools lined up.

Before anything I laid out the specimen, in this case a birch, and made sure everything would fit on one sheet. Then I checked to see if different parts of the plant were all represented, such as: catkins, and undersides of leaves.

Setting up the layout before the committing to its final resting place.

Setting up the layout before the committing to its final resting place.

Once I was sure of how everything is to be placed, I picked up the specimen and began dabbing it well, but not liberally, with glue. Glue is to be only placed on the surfaces where the specimen will make direct contact with the paper. (Too much glue can ruin the specimen and also it doesn’t look very pretty.)

Here I am using a surgeon's forceps, since it locks into place and holds the specimen steady.

Here I am using a surgeon’s forceps, since it locks into place and holds the specimen steady.

Once the glue is applied, swiftness and precision is the key to success, since you don’t want move the specimen once it has made contact with the paper (it tried once and it makes a mess). To help hold the specimen down while the glue is setting, little bags of sand can be used.

Here are two sand bags holding down some freshly glued pieces.

Here are two sand bags holding down some freshly glued pieces.

After a few minutes the bags can be removed and placed on another part of the specimen.

After a few minutes the bags can be removed and placed on another part of the specimen.

Once things have mostly dried and the specimen is pretty secure, little slips of gummed linen hinging tape can be used to hold down thick parts of the specimen. The little strips of linen harden like a cast that you would get at a doctor’s office.

Wetting the little "cast" strips.

Wetting the little “cast” strips.

The strips should be cut thinly, so that they don’t obscure of distract from the specimen too much, and they are to be placed at the far ends of the specimen. This also applies to the number of strips that should be used, since you don’t want the specimen to end up looking like a mummy (the embalmed type).

All glued, strapped, and secured.

All glued, strapped, and secured.

Once completed, the specimen should be secured, flat, and pretty to look at. Now the specimen is ready to be labeled, accessioned, sorted in a dry, cool, and bug free place.

All glued, strapped, and secured!

All glued, strapped, and secured!

That’s it from the Herbarium, plus I am happy to say that my pressed crab apples, wild pears, and dahlias turned out well. Oh and before I go again, here are a few shots of the Herbarium itself:

Yes, the place I called home for two weeks.

Yes, the place I called home for two weeks.

Here is where Botany lives and works.

Here is where Botany lives and works.

Right across from Botany, the herbarium shelves are placed here where stacks and stacks of specimens live.

Right across from Botany, the herbarium shelves are placed here where stacks and stacks of specimens live.

See you soon!

5 Responses to “Pressed: The Herbarium”

  1. Rachel Hanson September 17, 2013 at 4:39 pm #

    Wow! Terry looks so great, it looks so fun!

  2. kce0 September 22, 2013 at 2:48 am #

    Reblogged this on RHS/GCA Fellowship Experience and commented:
    Hello everyone! I am Terry Huang, the US counterpart to the RHS/GCA Interchange Fellowship and I will be posting my adventures along side Kasia. I hope you all follow us along our journeys across the Atlantic!

  3. Agnes September 23, 2013 at 11:18 pm #

    I would enjoy reading your descriptions of the specimens, I can only imagine what you write, especially for fragrance!

    • terrygardens September 28, 2013 at 6:24 am #

      Hehehe! Well, they were simple descriptions. I didn’t want to get too carried away with my first week…😉

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