I am inside the National Arboretum Herbarium
in Washington, DC.
And this is a stack of botanical specimens
collected over the course of several centuries.
Inside may be something completely unknown to science,
capable of curing my dyslexia,
and making a really good cup of coffee.
Alternatively, it may have been eaten by a beetle
sometime in the 1960s.
Alternatively still, it may just be a very old,
very boring squashed banana.
Let's take a look.
(gentle music)
When it comes down to it,
a herbarium is just a central repository
for plant specimens used in scientific study.
But why do we need to go to all that effort
of collecting our specimens
when we could just take a photograph
and put it up online?
To find out,
I've come to the US National Seed Herbarium
just across the hall
from the storage room we were in earlier,
in order to find out how it works.
Here, they got everything ranging
from the tiny tropical orchid seed
to the massive double coconut.
Let's say you're a customs inspector
in the port of New York,
and you've just received a shipment of pineapple
from the West Indies.
At the bottom of the crate are a collection of seeds.
You're not sure what they are.
They're certainly not pineapple,
and you think they may be kutzu,
an invasive species
which would be devastating to local growers.
If they are kutzu,
then you really need to be turning the ship around
and, ideally, setting it on fire.
But if you do that and you're wrong,
then you've just destroyed a multi-million dollar shipment.
What do you do?
Well, you take a collection of seeds
and send it in bio-secure overnight shipping
to the facility here in D.C,
where the experts compare it to known seed samples
to find out what it really is.
Sure, you may be able to take photographs
of these different samples and look at them online.
And while that may be good enough for many purposes,
when you need to know the tiny differences
in color and texture,
that is just not going to come across on a photograph.
All the specimens in the world are going to be useless
if they don't store for long enough
in order for us to study.
As I found out quite disastrously
last time I came back from holiday,
even if you put it in the fridge,
organic matter will still break down.
Decay is caused by the growth of fungi,
bacteria, and insects,
which use the water and nutrients within our food
in order to grow.
Therefore, in order to stop decay,
we need to remove one of these three.
Obviously, removing the nutrients
is pretty counterproductive, given that the nutrients
are actually the plant specimens we're trying to study.
Therefore, our main focus is on removing the organisms
and also getting rid of as much water as possible.
Decay sets in as soon as we clip our specimen,
which means that we need to be preventing
those processes of decay as quickly as possible.
First up, we need to remove any visible bugs
that are on the sample.
These would be literally eating it as we go along.
But our next step is to remove the water content.
We do that by squishing between these two boards.
First up goes some cardboard.
We then have some blotting paper
in order to adsorb any moisture.
And then we put our specimen
between some sheets of newspaper,
including an identifier on the piece
in order so we can compare it
to the notebook we've taken
for the observations made on the day.
We put a bit more newspaper in,
along with some more cardboard,
and we can include more specimens.
We keep building up this sandwich
again and again and again,
until we've got all the specimens we collected for that day.
Once we've got our sample sandwich,
the next step is to remove as much water as possible
by adding pressure.
We start out by strapping it together,
and then adding more force.
You can do that by using jack screws,
although, because we don't have any,
I'm just going to stand on it
and see how long it takes to squeeze out water.
As it goes, we continue to tighten the straps,
and we then come back to it
after it's had some more time to dry.
Once that's ready, we get our sandwich
and send it off to D.C.
When it gets to the Herbarium,
our first step is to facilitate some further drying
by putting it into a hot box for about a day.
After it's done that drying,
we then send it to the freezer
where it cools at negative 80 degrees centigrade
for 48 hours.
This kills off any remaining insects and fungi.
The specimens get unpacked.
Some sooner than others.
And we use glue to mount these onto sheets
of acid-free cardstock.
A well-preserved sample can last for centuries.
This is a specimen of passiflora incarnata
collected in 2004,
and here we have the exact same species from 1900.
While the colors may be slightly more muted,
much of the detail, like in the flowers, still remains.
We keep track of colors with detailed description,
illustrations, and in modern times,
some color photography.
When it come to displaying the specimens,
we have two very different philosophies,
appropriately illustrated
by some of the collections of Isaac Martindale.
At the time of his death in 1893,
he had amassed one the largest private herbarium collections
in America.
First up, we have what I like to call the Pokemon approach.
Isaac's bound his plant specimens
inside some of these massive volumes.
While most pages will contain a specimen
and some description,
occasionally we find a page that's mostly blank,
containing information about a plant species
but yet with no specimen present.
What I think he's done
is treated plants like collectors cards,
written down every plant known to him
and then spent his days trying to catch them all.
While most early herbaria were stored using the book method,
in the 18th century, Swedish botanist, Carl Linnaeus,
instead decided to go for a different approach,
keeping his samples as unbound loose leaf.
This way they could be categorized,
studied in detail, re-categorized,
sent to institutions and categorized again.
This allowed for much better science,
but keeping track of all the pages
soon became a storage nightmare
requiring some rather innovative solutions.
Welcome to the compactor room.
54 rows of shelving holding 650,000 specimens.
They're organized according to the tree of life.
Upstairs, we have our ferns and conifers,
while down here are the flowering plants.
I'm now going to show you my favorite set of plants.
Coffee.
Many of these samples that we're going to see
were collected during the 1960s.
At the time, plant growers in South and Central America
were suffering from cultivars that were furiously interbred
and suffering from overactive diseases.
This triggered a US Department of Agriculture led
expedition to Ethiopia
in order to gather some of these original samples.
A row contains hundreds of folders
and thousands of specimens.
Each folder has a name on the front indicating
which genus that collection of plants belong to.
The different colors indicate where it was collected.
Yellow for Asia,
green for Africa,
and blue means that it was intentionally grown by humans.
When we have extra big samples
which can't be stored in the folders,
what we do is get a very large elephant to sit on them.
Or, alternatively, we just put them into a box
and treat them essentially the same as all the rest,
just happening to be in a large box.
When a researcher wants to look
at all of the coffee samples from South America,
all the curator need do is open up the row for coffee,
and then find the samples inside a red folder,
setting it out to be studied.
Finally, let's take a look at our stack of folders.
What they could contain is anyone's guess.
By chance, we picked a folder containing species
from the Aerva genus.
These specimens are from a range of habitats,
including Western Australia, Pakistan and Sailun.
This specimen apparently began it's days
in Isaac Martindale's collection,
where it was originally misclassified
as a completely different species
before the curator here put things right.
Native people would traditionally use these plants
to cure headaches.
Although today, they're more commonly deployed
as a soil binder in desert reclamation.
Despite our best efforts,
none of the folders have contained any species
which are that out of the ordinary.
In fact, the entire Herbarium had just undergone
a full catalog digitization,
which meant that everything was in pretty good nick.
During that process,
they had uncovered some new notebooks,
as well as some specimens
that had been misidentified.
However, in order to turn these
into new species discoveries,
we would need the assistance
of a subject matter expert
to do detailed comparative analysis.
While we may not have found the cure to dyslexia
with this group of folders,
along just this row, we expect there are 50 new species
preserved pretty well,
but yet undescribed by science.
According to this paper
by an international consortium of biologists,
we think there are roughly 70,00 plant species
that are yet to be described.
Around half have been collected,
but are awaiting they're true discovery
in the world's herbaria.
Best to get started looking.
This has been James Dingley
from the Atomic Frontier.
Keep looking up.
(gentle music)