We’re inside UC Berkeley’s herbarium: a
research collection of 2.2 million dried plant specimens! In our next episode, we’re going to be talking about how scientists use herbarium specimens in their research, but first we’re going to show you how plant biologists collect and prepare plants to add to the herbarium.
Let’s go! *intro music* Welcome back to Science In Real Life! I’m Molly, and I’m here with Joyce Chery and Carrie Tribble, who are PhD students in the Department of Integrative Biology at UC Berkeley. Hi! Well, we were just in the herbarium, but what’s an herbarium? A herbarium is a collection of plants preserved for research. So you guys will be using herbarium collections in your graduate work? Absolutely. All of my research questions come from studying the morphology and anatomy of the diversity of woody vines from the tropics. I do this by studying the plants in their natural habitat, but I also benefit from making a collection of samples for further study. And I can use them for my research, but so can scientists in a hundred years if I
preserve them in a herbarium. So like Joyce, my research questions are focused on the evolution of plant morphology, but I’m interested in the evolution of
underground structures like tubers and rhizomes. And while those structures are often not collected in herbarium samples (though they should be), I’m interested in when and where these plants have been collected over the past 150 years, and herbarium samples are a record of that. We both study plans that are from Latin America, so they don’t grow here at Berkeley. Today we’re going to be collecting plants here on campus! Let’s go in and botany adventure! People have been collecting plants for
thousands of years for a variety of reasons: for medicinal discovery, to finding new crops, to finding the hottest new flower for your garden, and more recently, for scientific research. And I think it’s important to keep in mind that plant collecting has this complicated history that is tied up with European colonialism, with the exploitation of natural resources, and of the people that lived in those regions. Some examples are the rubber trade in
South America and the spice trade in Asia. Right so a couple hundred years ago
when plant collecting was becoming a craze, countries were pouring in money to fund
expeditions to exotic places to discover new plants. But at the same time, average citizens were catching on, and if you had the largest plant collection, you were the coolest kid in town. And that’s something that I kind of miss. And now we’re going to collect a plant! How bout this one? There are a few materials that we’ll
need to collect this plant today. A plant press, a newspaper, a marker, a notebook and pencil, a GPS, clippers, and of course a targeted collection plan. This means I should know what kind of plants I’m looking for, or at least a research question before I head out into the field to have the most efficient field expedition. It’s important to know what parts of the plant to collect. The whole idea is to be able to use these plants as research specimens in the future, so we need to collect as many parts of the plant as possible to ensure the usefulness of a specimen beyond the present study. The very basic things to capture in a collection are: the full shoot, tops and bottoms of the leaves, and fruits and flowers if present. Now let’s collect this plant! It’s important to attach a unique collection number to each specimen and keep a note of it in your collecting notebook. Yeah when i was working at the New York Botanical Garden I’d hear these great stories about how some of the famous botanists would compete for the highest collection numbers. Some of the most prolific ones have numbers in the tens of thousands! A good plant collection is only as good as the notes accompanying that specimen Because it will eventually become an herbarium specimen, we have to record as many observations as possible about the collection. A general rule is to at least include observations that will be lost when the plant is dried and mounted. These include: the precise location where
the plan is collected (that’s why we need the GPS), elevation, scent, flower or fruit color, habitat, height and width, the diameter of the trunk if it’s a tree, and the hypothesized identification of the plant. So now that we have our collected specimen, it’s time to preserve it in our plant press. So we’re going to open up the press and here we have a newspaper where we’ve written today’s date, the collection number, as well as the name of the collector. And we’re going to open up the newspaper and then place the specimen inside. And we’re going to carefully arrange the specimen so that we have all of the features that we intentionally collected displayed. So that includes the bottom as well as the top of the leaves, the flowers and fruits if present. And we’re going to try to
carefully close the newspaper, maintaining the plant in the arrangement
in which we placed it, and then close the plant press, sandwiching the newspaper between two pieces of cardboard and between the two sides of the wooden frame. And now we’re going to use these straps to apply pressure to the plant and make sure that everything is nice and lined up while we do this, and then just tighten those straps up to apply as much pressure as possible Minus the GPS, this is the technique that botanists have been using to preserve plants for hundreds of years. And the next step of preservation is to dry the plant. We’re going to head to the herbarium directly, where we could dry it there. We take our plant press and place it into the heater to make sure that the warm air gets through the newspaper and the cardboard, drying our plant. We leave it here for about five days to ensure that the drying process is complete. Oh man Berkeley botanists have been pretty busy! Oh yeah! Next time on Science In Real Life, we’ll show you how a plant gets added to UC Berkeley’s collection of 2.2 million herbarium specimens, and explore how that collection is used for botanical research- stay tuned! This episode was brought to you by the American Society of Plant Biologists