Collected works (pdf) - Royal Botanic Gardens, Kew

ALL IN A DAY’S WORK
Collected works
Away from the public gaze, the Herbarium’s unique and extensive collection of
preserved plant material is at the heart of all Kew does, as Carolyn Fry discovers
PHOTOGRAPHS BY JOHN MILLAR
You could be forgiven for not noticing
Kew’s Herbarium as you head
for the Main Gates. Yet the 18thcentury
Grade II listed building, set
back behind railings on Kew Green, is really
Kew’s beating heart. Within it are some seven
million dried plant specimens, gathered over
the centuries by esteemed collectors including
Charles Darwin, David Livingstone and
John Hanning Speke. These specimens
represent 98 per cent of all the genera in the
world and are meticulously filed in systematic
order, according to the characteristics of
their flowers, leaves, stems, fruit and roots.
As techniques such as DNA testing shed
new light on the relationships between plant
species, Kew’s plant taxonomists – botanists
who specialise in identifying, naming and
classifying plants – constantly keep the collection
up to date by renaming specimens
and tweaking the classification system. It’s
a complex and labour-intensive task, but a
vital one. The collection underpins much of
the botanical work conducted around the
world, and it also helps Kew’s scientists seek
new plant-based medicines, identify illegally
trafficked species, and locate elusive seeds
for conserving in the Millennium Seed Bank.
More than 100 people work in the
Herbarium, including plant taxonomists,
staff who organise and create the collections,
digital map experts and scanning
technicians. To understand what their jobs
entail, it helps to know a little about how
plants are classified. Essentially, Kew uses a
system called the Bentham-Hooker classification,
which groups plants into families
according to their form and structural
(morphological) features; these are then subdivided
into genus and then species. If you
want to find a dried specimen of a plant in
the Herbarium, you look up the family name
in the Red Book Family Index, and this
gives a code indicating exactly where in the
Herbarium the plant family is kept.
“We work largely on tropical flora, so we
rely on gifts of plant material from other people,
and in exchange we provide a naming
and identification service,” explains taxonomist
Gwilym Lewis. “If you’re standing
there with a plant in one hand and an identification
manual in the other… you can get
the specimen from the cupboard and compare
it with what you have. If it’s not right,
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ALL IN A DAY’S WORK
ALL IN A DAY’S WORK
Right and below: Emma
Tredwell looks after the
70,000 bottled specimens
in the Spirit Collection
Left: an expert in Latin
American beans, Gwilym
Lewis has worked in the
Herbarium for 30 years
Below: staff undertake
family ‘sorts’ to decide
which family each
specimen belongs to
Left and below: plant
specimens are lent by
or loaned out to research
institutions worldwide
All specimens belonging
to the same plant family
are stored together in
adjacent cupboards
Right: 98 per cent of the
world’s plant genera are
preserved and stored
in Kew’s Herbarium
The herbarium sheets
displayas many aspects
of the plants as possible,
so they can be studied
but it’s similar, in a systematically organised
herbarium you just have to look at neighbouring
files to find the matching specimen.”
Because not all plant specimens can be
pressed, the Herbarium also holds a Spirit
Collection. This comprises 70,000 jars of
fleshy fruits and complex flowers, such as
orchids, stored in ‘Kew Mix’, a cocktail of
methylated spirit, formaldehyde, glycerol
and water, prepared by Spirit Collection manager
Emma Tredwell. “The formaldehyde
fixes the plants as they are, the alcohol stops
fungus and mould attacking the sample, and
the glycerol prevents it going brittle,” explains
Emma. “These samples are cross-referenced
to the Dried Collection.” Stored in an array
of boxes, the Dried Collection comprises
plant parts that are too big or awkwardly
shaped to be pressed and mounted, such as
large fruits or long palm fronds.
Around half of the Herbarium staff are
expert plant taxonomists who constantly
hone the filing system by identifying and
classifying new plant material and updating
existing records. In addition to staff who
specialise in monocot or dicot plants (those
with one seed leaf or two), there are five
regional teams that study the floras of dry
Africa, wet Africa, South America, temperate
regions and South-east Asia. Between
them, these groups curate, name and
update plant specimens stored in all corners
of the Herbarium.
Gwilym, who has worked at Kew for
30 years, heads up the Leguminosae team.
“I specialise in the peas and beans of Latin
America,” he explains. “My main fieldwork
patch has been Brazil. I manage a small
team of people and conduct research on the
economically important bean family, which
mainly involves finding and describing new
plants and getting them next to their brothers
and sisters in the big system that is the
tree of life. Then I write scientific papers
and books to distribute that information to
as wide an interested audience as possible.
I do a little television and radio too. It’s very
eclectic work and very interesting – there’s
never a dull day.”
Gwilym is just one of about 50 scientists
who work at the Herbarium and in other
countries from Madagascar to Peru. Added
to this, regular visits by students and expert
botanists from around the world means
there is a constant flow of people passing
through the building, from both the UK
and worldwide, searching for and exchanging
plant information.
Sitting among the potted palms on the
Herbarium’s top-floor verandah, watching
the Thames below, Gwilym tells a story
from the late 1980s that demonstrates the
relevance of the work of Kew’s Herbarium.
The HIV virus had just emerged, and scientists
were keen to seek out plants
containing anti-viral drugs. They found a
promising chemical in Castanospermum
australe, a tree endemic to eastern Australia.
It only existed in small populations,
so the researchers approached the Herbarium
to see if it had a close relative that
would yield the same or a similar drug. After
much systematic detective work, scientists
at Kew found exactly the same chemical in
a group of plants in South America, and
with permission collected samples of one
species in the Amazon rainforest. “Only
someone who identifies and classifies plants
could have pointed researchers in the right
direction, because without that knowledge
you would never have thought to look in
South America,” says Gwilym.
“There’s a perception that a lot of woolly
minded, grey-haired, eccentric hobbyists
sit in the Herbarium fiddling about with
whichever plant group interests them and
that it doesn’t matter to anyone else,” he
continues, “but the Herbarium, its collections
and specialist taxonomists are central
to all botanical research.”
Anyone studying a particular plant
group and the relationships between different
species within it will generally need to
look at many different specimens. So every
day Kew’s staff borrow specimens or accept
gifts of material from herbaria around the
world, and send out samples to scientists
working in other countries. Imports of
material are not allowed to enter the
Herbarium building until they have been
frozen for three days at -35°C. This ensures
that any pests that might eat the specimens,
such as herbarium beetles, don’t make it
into the collection.
Once the specimens have been given the
all clear, they are taken to the Collections
Management Unit. Here, piles of specimens,
all sandwiched between sheets of
ADDITIONAL PHOTOGRAPH: ANDREW McROBB/RBG KEW
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ALL IN A DAY’S WORK
ALL IN A DAY’S WORK
Right: the digital maps
made in the GIS Unit
are a valuable aid to
conservation work
Left and below: the
collection is a vital
resource for Kew’s palm
expert Bill Baker
Right: the herbarium
sheets are being scanned
so they can be made
available online
Left: with 30,000 new
additions each year, space
is rapidly running out, so
a new wing is being built
Above: whenever DNA
research uncovers new
plant relationships, the
records must be updated
Plant parts that are too
awkwardly shaped to be
pressed are instead dried
and stored in boxes
Above: pheromone traps
are used to help protect
the collection from pests
such as cigarette beetle
More than 100 staff
work in the Herbarium,
from plant scientists to
digital map experts
acid-free card, cover a large desk and fill
walls of wooden pigeonholes and metal
shelves. This incoming material is carefully
labelled, then awaits collection by the
botanist who requested it. Outgoing material
is placed in mailboxes according to their
destination – usually universities or other
herbaria. As backup to the military-precise
operation, all material is entered into a
computer system, so each plant specimen’s
journey around the world can be traced at
the click of a mouse.
Computers are also proving their worth
in other areas of the building. As part of
Kew’s remit to make its collections more
widely available, it has begun digitising and
barcoding some of the Herbarium specimens.
Each day, a dedicated team inputs
information about when and where a plant
was collected, together with its present
name and any past variations, to a database
called HerbCat (not to be confused with
the Herbarium cat, a black and white stray
called Fluff!). This information is accessible
over the internet. By June 2007, the
Digitisation Department had catalogued
more than 250,000 specimens.
Meanwhile, the GIS Unit (Geographic
Information System) is dedicated to producing
digital maps. By inputting environmental
data such as altitude, soil type and annual
rainfall, the team can show botanists where
they’re most likely to find certain species.
Or they can use information from herbarium
specimens to plot maps showing where
certain rare species are concentrated. “We
are about to finish a vegetation map of
Madagascar,” says spatial information scientist
Susana Baena. “In Madagascar, the
authorities are trying to increase the amount
of land that is set aside for reserves. They’ll
be able to use the vegetation map to decide
which areas are the best ones to protect.”
Politicians around the world can make conservation
decisions based on the work of
Kew’s GIS Unit.
Today, next door to the present site,
a new £15 million additional building is
under construction. This will enable the
Herbarium collection to grow by some two
million specimens, so at its present rate
of 30,000 new additions a year it won’t be
full for a good few decades. Solving the
problem of storage has created a new
conundrum for the Herbarium staff, however
– whether to do away with the old
Bentham-Hooker system of classification in
favour of a more up-to-date filing system
based on recent molecular studies. Some
botanists have suggested switching to an
entirely new filing system based on DNA
sequencing. Botany students now learn
this method of classification, so in many
ways it makes sense to switch, but changing
to the new system represents a massive
upheaval for staff in the Herbarium and
across the Gardens. It’s just one of the many
important dialogues that engage the Herbarium
staff every day.
Whichever classification Kew opts for,
the plants will still be professionally curated
and readily accessible for generations
to come. This is what makes the Herbarium
and its experts such a valuable resource.
“A herbarium with specimens organised
systematically underpins all other branches
of botanical science,” asserts Gwilym. “The
study of plant diversity cannot progress and
has no working hypothesis without us.”
The Herbarium might not be the focus
of most visitors as they approach the
Gardens’ Main Gates, but within its rabbitwarren
of corridors and cubby holes, Kew’s
experts are daily boosting our understanding
of the world’s flora and disseminating
that knowledge to help preserve plant biodiversity
for the future.
n
Carolyn Fry is a freelance science writer and
author of the BBC book The World of Kew
ADDITIONAL PHOTOGRAPH: RBG KEW
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