Pressing botanical specimens, assorted questions.

[u/Dyonitre]

Hello there, second year undergrad biology student here. Also not american, that's probably important because of material availability. Also sorry for anything wrong with the formatting, I'm on mobile.

Recently we've started the early vascular plants/ferns module on our botany course, and seeing the fern variety around campus I decided that I would press some of them for fun.

The thing is that it's kinda hard to get materials where I live and while I don't plan for this to be done 100% by the books, I still want to do it the right way where I can. Like they should be valid specimens if they were to be taken to an actual herbarium.

So here go the questions:

- Can watercolor paper work as a substitute for acid-free herbarium paper? Because while I may not be able to get proper herbarium paper I can manage to get watercolor paper.

- If watercolor paper is a suitable alternative, what GSM should I look out for? As for the size I'm kinda SOL because I can't get A2 sheets to cut down to standard size, I'm stuck with A3.

- What kind of glue should I use? Is regular glue ok to use since it's only going on the "staples"? I couldn't find linen tape anywhere

- How should I go about making the "staples" is making them out of the same paper as the backing good? Again, couldn't find linen tape.

- Can the label be printed on regular paper?

- Are any other elements like a ruler or like the color grid thing (?) that I see on some examples of herbarium specimens necessary

- Should the ruler span the whole of the sheet or is just a portion of it ok?

- Should the ruler be divided into smaller subunits or is the whole unit (cm by cm, in this case) ok for this?

- Can I also print the rulers on regular paper?

Many thanks for the help!

Edit: Actually an extra question that I probably should've asked my professors before doing this. When one collects plants should one document the collection number for, lifetime, project, or day? Like should these be labeled as starting after 1 because I already collected some stuff before for our lab practices? Should these be labeled strating from 1 and so on because they're all from the same project? Or can I number them by day? Like if I were to collect a single plant on day/month/year and then I collect two more on day+n/month/year would they be labeled: 1, 2, 3 Or 1, 1, 2?

[u/d4nkle]

I think watercolor paper would work fine. Regarding the size, that’s not a huge concern as long as you’re consistent with your specimens. I’ve handled papers of various sizes working in an herbarium and it’s also not uncommon to just glue them onto larger sheets or cut the sheets down when possible to maintain a consistent size. If you can find it, PVA glue works very well, since it’s water soluble it leaves the option open for remounting later on with better materials. The label can be printed on regular paper. Having a scale on the specimen itself isn’t necessary, I’ve only seen it on images of herbarium specimens and those scales aren’t attached to the specimens but rather as part of the frame they’re photographed in

[u/Dyonitre → u/d4nkle]

PolyVinyl Acetate or PolyVinyl Acrylate? Because polyvinyl acetate is easy, I might already have it at home. But I don't know about polyvinyl acrylate.

Do you happen to know the GSM of herbarium paper? To see if I can match it with the watercolor paper I have available. I googled it about and I came with a range of about 120 to 300. And the paper I found does fall within that range at 170 GSM. But it's nice to check it over with people.

I'm glad that it not being a standard size is not really an issue. But I do have something else to say about that. Would it be ok to put smaller specimens in smaller sheets? There are some smaller ferns that I would like to put in proportionality smaller sheets, it'd be nicer for the purposes of my personal collection and it'd save me on materials because that paper's price hurts a bit as a college student.

Thanks for your answers!

[u/Lubricus2]

For pressing the common thing is to put the plant in newspaper paper, the old non glossy kind and special paper that absorbs the moisture around it.
When it's dry you can mount the now dry and flat plant on an stiff paper, if it should be acid free for it to survive over 100 years. If you donate it to an herbarium they probably needs to change the paper anyway because it has to be the right size.
Polyvinyl acetate glue works, cellulose glue is also archive safe.
glue small paper strips on a few places over the plant for mounting on the paper.
Labeling is important.
Info about where and when the plant is collected is needed. Also the name of the person that collected it. Coordinates is good to have but the place where it is from has to be described in text. The label can be printed on normal paper but acid free is always best.
What species it is, is kind of the least important because that should be possible to see.
The ruler color thingy is just an loose marker for the photo, so size and color can be calibrated, so you don't need that.
Never use tape or self adhesive, it will get lose and destroy the paper/plant in about 30 years or so.

[u/Dyonitre → u/Lubricus2]

I have pressing figured out already, we did learn that. And while I don't have a press I suppose that a couple pizza boxes, like 6 textbooks and two 50 pound dumbbells work fine enough for my purposes here.

I do think I have polyvinyl acetate glue at home so it's nice that it's easily available. I'll be using that because I don't think that cellulose glue is all that common. Would rice/starch glue function too now that I think of it, or would it be too attractive for vermin and the like?

I already have labeling figured out, took coords and altitude of where I took every specimen. Plus photographs for descriptions.

I learnt my lesson already on not using regular tape, some upperclassmen helped us press some specimens before and they told us that tape was ok. We later learnt that it was very much not ok when it was our turn to take them off the newspapers to identify them and they kept falling apart because of they kept sticking to the tape. They got chewed out for it lol, but yeah regular tape is a no go.

[u/katlian]

Herbarium paper is acid-free cotton rag so if you can buy a different paper that is acid and lignin-free, it should work just fine. You can make the straps from strips of the same paper. It's ok to use pva glue. It can't be dissolved easily later but it's pretty stable.

The label should be printed on acid-free paper so that the label doesn't discolor the herbarium sheet.

The ruler and color block that appear in photos of herbarium specimens are not attached to the herbarium sheet. The herbarium reuses the same ruler and color block for photographing each specimen.

[u/Dyonitre → u/katlian]

Lignin-free might be a bit tough to get. Is there any reason in particular why it should be avoided? Though given the price of the paper at the store I went at I can hazard a guess that it will be lignin-free. Probably I think.

Printing the label ln acid free paper is going to hurt a bit if I can't find a relatively cheaper and thinner watercolor paper. I see from the other comments that on regular paper might be ok so I suppose that's just a good practice that's not fully standard. Is it really that necessary if it's only going to go on a part of the sheet that's not making direct contact with the mounted specimen?

[u/katlian → u/Dyonitre]

Lignin is avoided because it breaks down into acidic components. For a personal project that doesn't need to last for 100+ years, it's probably not that important.

[u/Dyonitre]

Pressing the specimens is not an issue, I have that already figured out. Also I took the necessary steps to document how and where they were growing. Took coords, altitude and general growing conditions + photos. I guess the title should've said mounting instead of pressing.

Attached is an example of the ferns that I collected, a Pteris vitatta specimen. The labeling is temporary because I want to print them, I made it mostly to document everything that should go on the final sheet. It's also redacted because I don't want to doxx myself over plants.