Inside Iowa State’s Herbarium With 700,000 Plant Specimens

16:32 minutes

A woman is enthusiastically re-organizing papers with pressed plant samples on them.
Deb Lewis is curator of the Ada Hayden Herbarium inside Bessey Hall at Iowa State. She is handling historic specimens collected by George Washington Carver and Ada Hayden. Credit: Christopher Gannon, Iowa State University

Herbariums are plant libraries—they contain fragile specimens of plants collected from near and far, and they are meticulously described and cataloged so that someone can reference them in the future. At Iowa State University, the Ada Hayden Herbarium contains more than 700,000 specimens, about half of which are from Iowa.

Ira talks with herbarium’s director, Dr. Lynn Clark, and curator Deb Lewis about how plants are preserved, why herbariums are so important, and what it takes to manage a plant archive.

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Segment Guests

Deb Lewis

Deb Lewis is a curator at the Ada Hayden Herbarium in Ames, Iowa.

Lynn Clark

Dr. Lynn Clark is the director of the Ada Hayden Herbarium in Ames, Iowa.

Segment Transcript

IRA FLATOW: This is Science Friday. I’m Ira Flatow. If I say herbarium, what do you picture? Let me make it easy.

Herbariums are basically plant libraries. They contain fragile specimens of plants that are carefully documented and stored away so that researchers can study them for years to come, possibly centuries. We’ve brought SciFri to Ames, Iowa this week. We’re at Iowa State University. The Ada Hayden Herbarium contains more than 700,000. 700,000 specimens collected from the Hawkeye State and beyond.

Joining me here in the Iowa Public Radio studios are Dr. Lynne Clark, director of the Ada Hayden Herbarium, and curator Deb Lewis. Welcome to Science Friday.

LYNNE CLARK: Thank you.

DEB LEWIS: Thank you.

IRA FLATOW: I’ve got to get the Lewis and Clark out of the way first, right. You’ve heard that just a few times already.



IRA FLATOW: I’ll bet you have. Deb, if I walked into your herbarium, what would I see?

DEB LEWIS: First of all, you would just see metal cabinets. Sort of resembling a gym locker room. But if we opened those cabinets, we would find dried and pressed plant specimens, or maybe packets of mosses and fungi, or similar things like that.

IRA FLATOW: Rows and rows of cabinets.

DEB LEWIS: Rows and rows. Yes.

IRA FLATOW: Because you have 700,000 specimens in there.


IRA FLATOW: Wow. And Lynne, give me an idea of what the range of things that you have in those cabinets.

LYNNE CLARK: So we would have, as Deb mentioned, the fungi, the mushrooms, lichens, like the stuff that grows on tree barks. You actually pry the bark off to make the specimen.

IRA FLATOW: Do you bring the bark in with it?

LYNNE CLARK: Or the rock or yeah.

IRA FLATOW: That’s cool.

LYNNE CLARK: Wherever it is, that’s what you grab. But also the plant kingdom, including things like mosses and liverworts, ferns, pines and their relatives. All the flowering plants. So all the things like grasses, daisies, mints.

IRA FLATOW: Wow. Deb, I know this is like asking about your children, but I have to ask you, do you have a favorite specimen in your collection.

DEB LEWIS: Well, I for my master’s, I studied a group of plants called pimpernels. But I also really enjoy coming across specimens that were collected by Ada Hayden and others, George Washington Carver, who I think we’ll get to in our discussion a little bit. And those very important historical collections.

IRA FLATOW: Do you look at any just for fun when you go in there?


IRA FLATOW: Yes? Yeah?

DEB LEWIS: We often give tours of the herbarium, and as we do so, we get to pull out some of our favorite plants. And so it’s like getting reacquainted with those fun plants again.

IRA FLATOW: Do you have one that you?

LYNNE CLARK: Well, I work on bamboo, so.


LYNNE CLARK: The bamboos.

IRA FLATOW: That’s a hot topic these days.

LYNNE CLARK: It’s a very hot topic. And it so happens that the bamboo cabinets are facing the main entrance. And so, Deb usually pulls some out. And I always do as well, so.

IRA FLATOW: Cool. Cool. And why, Lynne, is it so important to maintain herbariums? What do they do for us?

LYNNE CLARK: Well, they do a lot of different things. There’s the basic biodiversity documentation. Because every specimen has a label that indicates where it was collected, who collected it, the date, anything else like substrate that might be really important. And we all certainly, nowadays, we always georeference the specimens. So we actually put the coordinates. We go back and do the georeferencing for specimens that were collected before that was standard practice.

So going with the library comparison, every specimen is like the page of a book. And so we can document the distribution of a species, its flowering times. You can take pollen off of it. If you’re studying fossils, you need to identify pollen. This is a standard use for herbaria. Just to get data from the specimens. If I have to write a description of a new bamboo species, which I do a lot, I go to the herbarium, and I look at all the variation that I can find so I can get data. We can get DNA.

IRA FLATOW: Right. Of course.

LYNNE CLARK: Out of specimens.

IRA FLATOW: And as things are going extinct, now, right.

LYNNE CLARK: Yes, absolutely.

IRA FLATOW: DNA is even more important.


IRA FLATOW: What makes the Ada Hayden herbarium so special, Deb?

DEB LEWIS: Well, for one thing, we document the 2,000 plus species of flowering plants that occur here in Iowa, as well as, as Lynn mentioned, the mosses, fungi and other things that we keep in the herbarium. We have special collections that were made by our mycologist, Dr. Louis Tiffany. It’s always fun to come across her specimens. Those collected by Ada Hayden, that we’ve already mentioned. And even George Washington Carver.

IRA FLATOW: Let’s get into them. Let’s talk about Ada first. As you say, the herbarium is named after Ada Hayden. Who was she?

DEB LEWIS: Well, she was an Iowa farm girl who grew up just North of town. She loved plants just throughout her life, even as a child. Their farm had an area that couldn’t be plowed and put into agriculture. So she was able to collect plants from those prairies and wetlands that were left on the farm. And that got her off to a great start. She, while still a young woman, met Louis Pammel, who was on the faculty at Iowa State, as a botanist, and he invited her to come and study at Iowa State. And she got her bachelors, her masters, and was the first woman to get a PhD from Iowa State in any field.

IRA FLATOW: Really? Wow.

DEB LEWIS: Yes, and only the fourth overall.


IRA FLATOW: Wow, and Iowa State land has a very famous alum, as we talked about it before, George Washington Carver. A pioneer in agriculture and botany, especially his work on peanuts. He was also the first Black student and later faculty member at Iowa State. So how is his legacy preserved at the herbarium?

LYNNE CLARK: It is– takes the form of several hundred specimens. He collected both flowering plants and a lot of fungi. About, what, 500 fungi? 600, something like that, 600, and about 300 specimens of the flowering plants. So this is the largest collection of Carver specimens. When he went to Tuskegee, he kept sending stuff back. He and Pammel were very close. They were about the same age. Pammel was obviously a very forward thinking kind of guy.


LYNNE CLARK: I mean, he really contributed to the herbarium. He didn’t found it, but he really enlarged it. But he mentored people like George Washington Carver and Ada Hayden. The specimens are filed in the herbarium.

IRA FLATOW: When you open up the drawers or the doors, do you get a little rush? A sort of a little– I’d be a little like tingle. I’m opening up some very famous work here, right?

LYNNE CLARK: Absolutely, no. And a lot of his labels, we relabeled many of his specimens because we had to put the fungi into packets of archival paper. They were not stored that way originally. And I spent a good amount of time as a grad student retyping those labels, but we saved all of his handwritten labels. So those are in the packets or sometimes attached to the sheet of the specimen. So you can actually get a sense of his– you can read his handwriting.

IRA FLATOW: That and same way you feel about that.

DEB LEWIS: Yes, definitely. It’s always fun to be able to pull out George Washington Carver specimens and have them on display, or to talk about Carver and Hayden.

IRA FLATOW: Yeah, yeah. Let’s come back to the present day for a moment. And let’s say that I knock on your door. I’m holding a brand new plant species that I think I’ve plucked from the woods. How do you go about preserving that? First, how do you verify it? Or know what you know. You’re just taking my word for it? What do you– what’s the process?

DEB LEWIS: So the first thing is we have to preserve the specimen.


DEB LEWIS: And so we would wash off, knock off the soil, and then press it between sheets of newspaper. And then we have boards that we tightly tie around it and we have a dryer. So we go in there. And then it would end up being mounted on archival paper with the label. But at any point after it’s dried, we can study it to get that data that I was talking about. How big are the leaves? How hairy are they? What is the flower like? All the different parts that we would have to know about.

And then we have in addition to all the specimens, because you can compare specimen to specimen, but we have lots of books that have identification resources in them. So we call them dichotomous keys. And so you actually go to the, you know, the group of the plant, whatever it happens to be, and you have a series of choices. And, well, is it like this or like this one? Like this or that? And you go all the way through. And if you can’t reach a satisfactory answer, then you probably do have a new species.

IRA FLATOW: Do I get it named after me?

DEB LEWIS: No, that’s considered really tacky, to name it after yourself. To name it after yourself.


DEB LEWIS: The trick is to get somebody else to name it after you.

IRA FLATOW: Yeah, well, see, I’m new at this, so I don’t know. Lynne, what’s the weirdest plant in your collection? And what makes it so strange?

LYNNE CLARK: Well, the weirdest plant.

IRA FLATOW: Yeah. You have a fun fact about, you know, one of your plants?

LYNNE CLARK: I’m trying to think. We have so many. There’s so many strange things.

IRA FLATOW: Wait a minute. Wait a minute.


IRA FLATOW: There are so many strange things? Maybe that’s what I’m asking. What?

LYNNE CLARK: Strange, of course, depends on the context. But people walk in and they don’t know that we have this huge collection of bamboos from South America. People don’t know that we have–

IRA FLATOW: What’s it doing in Iowa.

LYNNE CLARK: What’s it doing in Iowa. We actually one of my former students and I named a bamboo species from the United States. We have native bamboos.


LYNNE CLARK: In the U.S, but there’s plants that, for instance, there’s parasitic plants. They don’t make any chlorophyll, so they don’t photosynthesize. They actually have connections through their roots or through fungi to other plants.

IRA FLATOW: Interesting.

LYNNE CLARK: And they are bizarre looking. They’re not green. They’re white, or they’re pink, or they’re red or something. So to me, those are some of the really oddballs. But to a lot of people, you know, a bamboo might be a strange plant.

IRA FLATOW: Can some of your samples last for centuries?


IRA FLATOW: Yeah. Tell me about that.

DEB LEWIS: Well, once they are pressed and dried and stored in conditions that will help to maintain them, and we use archival quality supplies whenever we are processing the specimens to so that, you know, not only will the plant hold up, like people have probably maybe collected a four leaf clover and stuck it in a book and then found it years later when they opened that book. And it still is intact. Well, we similarly dry things, as Lynn described, with using a plant press. And they will hold up, we say, virtually forever, as long as the paper that supports them, the paper that the labels are printed on, all of the inks and things that are used on the specimen. If those are archival quality, then they will hold up for hundreds of years.

IRA FLATOW: But I thought I heard you say you press them with newspaper when they–

LYNNE CLARK: Initially.

IRA FLATOW: Oh, initially, they’re not staying on the newspaper.

LYNNE CLARK: You’re not going to stay in the newspaper, right.

DEB LEWIS: No. No. They end up– it’s the– because you don’t want to use high quality stuff to do that initial step.

IRA FLATOW: And of course, I imagine researchers and students from around the world want to come in and look through your archives. What kind of level do you have to be at to come in and use your library of stuff? Can I be just an undergraduate and say I want to look at this or?


IRA FLATOW: You know, writing a book.


LYNNE CLARK: We get visitors doing all sorts of things, and a lot of them are hardcore botanists. But we have– the herbarium has a very important educational function.


LYNNE CLARK: So we do have– we use them– we give tours to students from grade school on up. And we use that. I teach I’m teaching a class right now, I’m just finishing, on plant diversity. And that those students get a herbarium tour.

IRA FLATOW: Cool. Yeah.

LYNNE CLARK: We’ll use the specimens.

IRA FLATOW: I’m going to give you a question I usually give to researchers, but I think you could use this also, and it’s my blank check question. If you had a blank check, which I have here in my backpack and of course.

DEB LEWIS: Absolutely.

IRA FLATOW: And you had all, you know, you had unlimited resources. How would you– what would you do with that money to either increase the quality of your work, or research, or find something you can– any, you know, piece of hardware you need? Anything like that.

LYNNE CLARK: We could dream.

DEB LEWIS: Dream big.

LYNNE CLARK: Dream big, we certainly can.

IRA FLATOW: That’s what it’s for. That’s why you have the blank check. What would you do with it.

DEB LEWIS: Well, for one thing, our computers could certainly be upgraded. That we use to create labels and to capture label information from specimens.

IRA FLATOW: Maybe the state’s listening right at this moment.

LYNNE CLARK: We can hope.

DEB LEWIS: That would be very nice.

LYNNE CLARK: We would. But we also need to invest in people too.


LYNNE CLARK: To mount the specimens and to file them away and to make sure everything is correctly placed and to answer these questions that we get. We routinely get dozens to hundreds of questions about plant identification, for example. Or other questions. Or once in a while, we’ll get something for forensic analysis.

IRA FLATOW: And you get other–

LYNNE CLARK: All sorts of things.

IRA FLATOW: Yeah, because I understand that you get other herbariums getting lumped into yours, right? Like a few months ago, Duke’s Herbarium shut down.


IRA FLATOW: And which was a big surprise to everybody.


IRA FLATOW: So this is where you could– you could also use extra money, or?

DEB LEWIS: To, yes, we could use extra money to incorporate. Not that we want to be doing that. We would like to see a strong network of herbaria in many places.

IRA FLATOW: So that’s disconcerting to hear that these other herbaria are shutting down.

DEB LEWIS: It is, you know, think tornado. Redundancy, for one thing, but also that educational aspect, being able to have a local resource for people. Because many places, when they divest themselves of a herbarium, they are also not replacing the people who have that knowledge to use the herbarium effectively, and to teach about.

IRA FLATOW: Yeah. Are you hopeful about the future here of the herbarium? It’s safe?

LYNNE CLARK: We certainly hope so.


LYNNE CLARK: With having gotten the collections here from the other two state universities. We had, we are hopeful that will be reason enough to maintain the collection.


LYNNE CLARK: And that we, you know, rank so highly in numbers of specimens. We’re about 11th in size among University collections in the country.


LYNNE CLARK: Even though Duke is a little bit larger than us. So we know that unfortunately can happen. But we’re hopeful that– I mean, we serve sort of as the state herbarium of Iowa, because we are much, much larger than any other herbarium in the state.

IRA FLATOW: Well, let’s end on that hopeful note, then. I want to thank both of you for taking time to be with us today. Dr. Lynne Clark is director of the Ada Hayden Herbarium, and Deb Lewis is the herbarium’s curator. Thank you both for coming in and talking with us today.

LYNNE CLARK: You’re welcome.

DEB LEWIS: Thank you.

IRA FLATOW: Thank you.

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