Preservation of Specimen

This might seem like a weird question but what’s the best way to preserve specimen for a long time. I usually stick with fungi but also stick with a few plant species. My reason for asking here is because I’d like to here from people who’ve actually tried different techniques to see which works best. Is dehydrating the absolute best way? Is there any purpose for an amateur to preserve specimen anyway? I’d love any input.

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for plants, pressing and then mounting as an herbarium specimen is the most commonly used method. I am not sure with fungi. Making a personal herbarium can be fun as long as you are conscientious of where it isn’t legal or appropriate to collect things. But you can do weeds in your yard, trees in your area, etc without any issues

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Thanks for the input, I wasn’t aware of herbariums. :thinking: I might do this for the genus I love so it could show the difference between species visually

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Datura might be a hard one with those big fruits that some(?) species have, but i bet you could get some nice specimens

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I started my own mini-herbarium almost 30 years ago and although I haven’t added to it, I still have those specimens. I pressed them in a plant press and then mounted specimens on large index cards, stored in a file box, since I didn’t have room to do full-sized herbarium sheets. I’ve added images of a few of those specimens to iNat in recent years.

Examples:
https://www.inaturalist.org/observations/33441290
https://www.inaturalist.org/observations/27635775

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:thinking: I would probably have to add quite a bit of weight on top of them to get it to press right. It’ll be done though or I’ll die trying :sweat_smile:

Those are actually pretty cool. I’m beginning to warm up to doing herbariums for plants I like in general

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For thick and/or succulent plant parts, like large fruits, specimens are often made by pressing cut sections instead of the whole structure. Besides preserving the shape better, it helps them dry quickly enough to (hopefully) avoid rot and discoloration. For exceptionally succulent pieces, they are sometimes lightly salted to help draw out the moisture.

When you do have to cut parts, a parallel iNaturalist observation is a great way to document the original appearance!

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Does the color of specimen usually fade?

Depends on the species and the drying conditions. For pressed plants, rapid and continuous dry warm (but never hot) air passing through the cardboard press corrugates gives you the best outcome. (You will need to re-tighten the press as water is lost.) Material to be pressed should be as fresh as possible. But some species undergo significant change or loss of color no matter how ideal the conditions. Once dry, specimens need to be kept in dry room temperature conditions with as little light exposure as possible. Some helpful online references (you can google more):

https://www.floridamuseum.ufl.edu/herbarium/voucher.htm
http://herbarium.usu.edu/resources/learning_about_plants/making_specimens

Note that references written in humid climates will talk about including blotter paper cards in plant presses to help absorb moisture, while those written in dry climates generally will not. In dry climates blotter paper impedes rather than hastens drying.

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This book/pdf helped me out a lot:
[Collecting and Preserving Insects and Arachnids, I. Millar, et. al.,]
https://libgen.is/book/index.php?md5=8EC18DD62B3A41D685FCF1711E53F475

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A lot of small arthropods can only be identified by mounting on a microscope slide. As most of these species have incredibly short lifespans collecting is rarely a conservation concern. You kill many more of such insects driving to a site than actively collecting. They also take up much less storage space. So these are a reasonable collection target for a technically competent amateur.

There are some good videos from the usda showing the technique:
https://www.ars.usda.gov/northeast-area/beltsville-md-barc/beltsville-agricultural-research-center/systematic-entomology-laboratory/docs/sels-slide-mounting-tutorial-videos

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I’ve just been sent this advice about preserving waxcap fungi, Hygrocybe species, from Debbie Evans, a mycologist in North Wales.

Samples need to be dried at about 40C or below to preserve the microscopic features and a food dehydrator is used by many mycologists. However, an easy alternative way is to dry them on some sort of an open mesh tray over a radiator. It should take about 24hours depending on the heat and size of the specimen. Make sure the sample is completely dry, (will be brittle not ‘bendy’), before storing in a well labelled paper envelope and then sealed in a plastic bag perhaps with some silica gel if available. Ideally for long term storage the samples then need to be put in the freezer for a couple of weeks to kill any insects and their eggs.

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Put the plant in a folded paper (newspaper, usually). Press it and pass warm air over it to dry it out. For big fruits, slice them! For branches with thin leaves, use a bit of foam to keep the leaves flat. Label with location, date, and your name, on archival bond paper (available at any stationary or office supply store). (Name of plant is valuable too, but that’s the least important for the specimen.) Gluing the specimen to high quality (archival bond) paper if good for long-term storage, but it’s optional. Never glue the specimen to low-quality paper! Bugs sometimes eat dried plants; occasionally put your specimens in the freezer for a week to kill any bugs. When you don’t want your specimens any more, donate them to a herbarium. They’ll be cared for and used. (You can find herbaria near you using Index Herbariorum.) Note: Most herbaria take fungi, too. They tend to be more 3-dimensional, and they’re usually stored in a folded sheet of 8.5 x 11 paper. With label, of course.

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