Original subtitles

For centuries, people regarded plants

as solely the creation of God, and some still do.

Their variety had no human order to it.

Plants were here to be celebrated, not questioned.

As a botanist, I understand how plants are grouped into species.

And yet, 300 years ago, this simple concept was highly controversial.

To question the order of nature was to question God himself.

In the late 17th century,

scientific investigation began to erode religious certainty.

The new discipline of botany was thinking about plants in new ways.

What botanists were looking for, and are still looking for,

is how the plant world fits together,

understanding what is related to what.

Grouping plants is what we botanists call "classification".

It's not about making life easier, though that would be nice,

it's about revealing the natural order of the world.

Classification of plants is the basis of the science of botany.

Pioneering botanists really struggled to invent a system

so that knowledge could be passed on to future generations

And they began to glimpse a world

where bigger, better, stronger plants could be created.

For the first time, the study of plants rejected religious dogma

and embraced science.

Today, botany is at the forefront

of advances that will affect all our lives.

And how it got there is a tale of intrigue, of jealous rivalry

and of flawed genius.

It's the story of how science unlocked the secrets

of what, for me, is our most precious resource - plants.

This is the University of Oxford botanic garden.

I should, at this point, declare an interest

For 22 years, I've been director

of the most compact, yet diverse, collection of plants in the world.

I have the benefit of centuries of accumulated knowledge,

because this is the oldest botanic garden in Britain.

It was founded nearly 400 years ago to celebrate and encourage understanding of the plant kingdom.

At its most basic level,

botany enables us to distinguish between these berries.

That's important because this is St John's wort,

used by some to treat depression.

This is deadly nightshade, which will kill you,

and these are blackcurrants.

Botany can also tell us which plants are related to each other.

That may not sound important, but it's been known for decades

that this yew tree can be used to treat breast cancer.

So it was logical to look at plants related to it, to see if they also contained useful molecules.

Sure enough, its cousin over there is being used to treat leukaemia.

This one example shows how important it is to define and classify plants.

The first major breakthrough in the classification of plants

was made by a young man studying not here in Oxford, much as it pains me,

but in Cambridge.

John Ray is a name most people have never heard of.

Yet, for me, he's one of the greatest naturalists ever.

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As a student at trinity college, and armed with nothing more

than a hand lens and the personality of a 17th-century geek,

Ray glimpsed something that no-one else had ever seen - a natural order.

The 17th century was an exciting time to be a scientist.

This was the era when Isaac Newton uncovered laws of physics.

There were revolutions taking place in the world of science,

and botany is one of them.

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John Ray's pioneering work on classification

moved the study of plants away from superstition and towards science.

Ray did what field botanists do today, went out into the field,

collected plants and pressed them in his herbarium press,

brought them home and observed them.

The more he looked,

the more he began to see a pattern in the plants he collected.

This pattern would be his first great discovery.

Ray would have gone out into the Cambridgeshire countryside

and found purple loosestrife.

Purple loosestrife vary in a number of ways - some are taller,

some have paler flowers.

Some people would have said these were fundamentally different.

Ray said, "No. This is just variation.

"You get different plants coming from seed that has been collected from the same plant."

My children have different coloured eyes, different coloured hair.

That doesn't mean they're a different species. Probably.

He argued that plants can look different and be closely related.

He'd recognised natural variation between plants, and he went further.

John Ray realised that there is a set of characters

that remain unique to a group of plants, in particular, the flowers.

Inside those flowers, the seeds,

the seed vessel

and the outer parts of the flower, the sepals.

These were the characteristics that didn't vary within a species.

These could be used to define a species.

It may seem a bit strange today,

but before Ray, no-one knew what a species was,

let alone how to identify one.

For the first time, we had a clear definition of what was a species.

Defining species in that way was a huge step forward for botanical science

and was one of Ray's major contributions to botany.

His progress was short-lived.

Soon afterwards, Ray was kicked out of Cambridge.

In 1660, the monarchy is restored following the death of Cromwell.

On a point of principle, Ray refuses to swear a new oath of allegiance to King Charles II.

Had he stayed at the university, he may well have become as famous

as his contemporary, Isaac Newton.

Instead, he left Cambridge and walked away into obscurity.

He exchanged the cloisters of Cambridge

for rooms in a house owned by one of his students.

This is Middleton Hall in Staffordshire.

It's here that Ray made his next discovery.

He'd defined a species by those characteristics of plants that don't change.

Now he wanted to go further,

to see if species themselves can be organised and grouped.

He wanted to know if they could be classified.

When John Ray was living here at Middleton Hall,

he was able to get on with what he did best,

which was looking at plants.

He would collect things, bring them back

and...he saw things that other people missed.

He turned his attention to looking at seeds.

Flowering plants produce seeds. They all look quite different.

But when you cut them open,

Ray discovered that there seem to be two sorts of seeds.

When you take a bean seed and cut it open, it splits into two.

He then started cutting open other seeds.

When he looked inside these seeds, he found that some, like this iris,

didn't split nicely into two like that.

There was just one structure in the middle.

Ray had uncovered a fundamental split

in the plant world.

The first group that splits easily into two, he named the dicots,

and the other, the monocots.

As he looked at the structure of the plants in these two groups,

he found five more significant differences -

in the flowers, in the stems, the roots,

the first leaves to emerge

and the mature leaves.

He realised that any further advances in classification

could only come about by looking at the whole plant,

all of its features, bar none.

The man was a genius. He got it right.

He created order out of the chaos that is nature.

It's a testament to Ray's brilliance

that his principles of classification

are taught to this day, 350 years later.

So, as chaplain to the household, was there a chapel here...?

'These are the rooms where Ray began to crack the code of classification.

'Today, they're looked after by Dr Ian Dillamore,

'a trustee of Middleton Hall.

'Although it's open to the public and you can learn about his work,

'John Ray is hardly a household name.'

He's not better known because he wrote his serious works in Latin

and he could not afford to illustrate them.

His humility in not pushing himself was very important as well.

In the prefaces, he apologises for putting readers to the trouble

of reading what he has to say!

LAUGHING: That's terrific!

"Does the world need another book like this?" he keeps asking.

The answer is, "Desperately." There was no book like it.

All of his books stand quite distinguished.

The principles of classification that John Ray developed in the 17th century

were largely ignored.

The status quo was undisturbed.

Botanists, farmers and gardeners had to struggle on

with hearsay and superstition.

Ray got the science right but the publicity hopelessly wrong.

When you have a good idea, you need to...

SHOUTS: ..shout it from the rooftops!

That simply wasn't Ray's style.

Modesty is a trait that could never be levelled

at Sweden's most famous son of botany,

the self-styled "prince of the plant kingdom", Carl Linnaeus.

His approach was as far removed from that of John Ray as you could get.

For Linnaeus, botany was all about sex!

This is the student thesis of Carl Linnaeus.

He called it "An introduction to the courtship of plants".

When Linnaeus wrote about the sexuality of plants, it wasn't only novel, it was shocking.

Because he described the reproductive biology of plants

as if they were humans indulging in licentious and shocking sex.

This was just the first deliberately shocking step

in the career of botany's first celebrity,

the showman and genius that was Carl Linnaeus.

I've come to Uppsala in Sweden,

where Linnaeus began his extraordinary career.

Linnaeus just scraped into Uppsala University to read medicine.

He was a difficult, under-achieving student

and medicine was regarded as an inferior subject.

But while here, Carl became an expert in anatomy.

Plant anatomy.

While his fellow students concerned themselves with the bloody workings of the human body,

Linnaeus saw only flowers.

Linnaeus had been obsessed with the sex lives of plants

since he'd been shown their reproductive bits and pieces.

So he would look at a plant like euphorbia

and he would find a male part, called a stamen,

and a female part referred to as the pistol,

both present in the same structure.

But not all plants have the same number of sexual parts.

When he opened up this blue salvia, he found

two males and one female.

The males are the two with the yellow pollen on them.

The female is the one with the blue tip.

He looked in this penstemon, and when he looked inside this one,

he discovered not one, not two, but four stamens!

But still only one female.

The more he studied, the more he became convinced

that he'd found a way to classify the plant kingdom.

He argued that nothing could be more fundamental to a plant's identity

than its genitalia.

He believed he could order the vast diversity of plants

by their sexual parts alone.

In the hallowed halls of learning across Europe,

scientists were discovering the laws of their disciplines.

But botany didn't have any, and now Linnaeus thought he'd found them.

As he rather immodestly put it, "God created. Linnaeus classified."

For five years, Linnaeus continued to study - identifying, counting,

noting and describing the genitalia of plants.

With his research completed,

he was ready to publish.

So here's Linnaeus's Systema Naturae,

published in 1735.

For a book that changed the world,

it's...small, it's only 14 pages.

I like to think of Linnaeus's work

as like an 18th-century computer spreadsheet.

The most simple flower is one that has just one stamen.

Here we have those with one stamen.

Then there are two boxes in that column,

those with one female and those with two females.

Then the next column boxes are those that have two males.

All those plants only ever have one female.

When you get into three stamens,

there are flowers that have one, two or three females.

It's beautifully neat and tidy.

It works simply from the left-hand side starting with one stamen,

right the way across, to where it's more than 20.

Linnaeus knew if his system was to succeed,

it had to be accepted in England,

the most important and influential horticultural market in Europe.

He began what can only be described as a marketing campaign.

He sent advance copies of his Systema Naturae to the key players

and he set sail for England.

When Linnaeus arrives in London,

he's not yet 30 years old.

He has no money or friends in high places, he's shabbily dressed.

He doesn't even speak any English.

He carries his address in case he becomes lost or waylaid.

All he had going for him was his incredible confidence.

Soon after arriving in London, he headed for the Royal Society.

He assumed he'd have no trouble persuading the great and the good of the scientific world

of the significance of his Systema Naturae.

He'd then have access to all the important men of the kingdom.

He couldn't have been more wrong.

The doors of the Royal Society were shut firmly in Linnaeus's face.

His marketing campaign failed spectacularly.

The preview copies of his sexual system for ordering nature caused uproar.

Not because of the bold ideas,

but because of the language Linnaeus used to express them.

One critic condemned Linnaeus's system as "loathsome harlotry"

because "it was like a tour round the bed chambers of prostitutes."

In effect, our Carl had written the screenplay of a Swedish blue movie,

and the English were deeply offended!

None of which mattered to our young botanical voyeur.

He was convinced he was right and everyone else was wrong.

And anyway, he'd come to England to meet just one person -

the current holder of the title Linnaeus coveted,

that of the greatest horticultural authority in Europe.

His name was Philip Miller.

Miller was a diligent gardener

and, like Linnaeus, a determined self-promoter.

A clash of egos was inevitable.

Miller started his career as a lowly florist in the flower markets of London,

awash with new plants from around the world.

The arrival of this new wealth of plants brought great opportunities.

But it also came with its own problems.

What was causing consternation was the names. Take this, for example.

Known as American wisteria, Wisteria frutescens,

but also known as Mr Catesby's new climber.

Which is quaint, but it is not scientific.

Every country had developed different names for its plants.

These even varied from region to region.

There were no universally agreed names.

This made it impossible to share advice

when you didn't know if you were talking about the same plant.

Philip Miller spied the chance to make his name.

He would put an end to this confusion

by regulating the naming of plants.

To do this, he founded the Society of Gardeners.

Once a month they met at Newhall's coffee house in Chelsea

to discuss and name the flowers, trees and shrubs flooding in from the New World.

The purpose of the society was to compare such things as should be received from abroad

with those already in the English gardens,

and discover where the real differences, if any, lay.

Philip Miller felt that their whole profession,

the new science of botany, was in danger.

He wrote, "All the sciences have each their proper language,

"but botany alone has almost as many different languages as there are different authors."

Miller believed that, as the self-appointed most talented,

the Society of Gardeners would soon compile a catalogue

of all the foreign species growing in English gardens.

Sadly, the society collapsed,

overwhelmed by the enormity of the task.

But it made Miller's name.

He was appointed head of the most prestigious botanic garden in London, the Chelsea Physic Garden.

As he began his work,

Miller, who was never short of confidence,

promised that Chelsea would soon out-vie all other gardens in Europe.

And he was probably right.

In the 50 years Miller was here,

he utterly transformed the garden.

He was directly responsible for doubling

the number of foreign species successfully grown in Britain.

The purpose of a physic garden

was to grow plants with medicinal properties.

Miller went further.

He developed it into a centre of economic botany,

growing cotton and roots used in the dye industry.

A lot of the plants here have the second name tinctorius,

which implies that they were used as a dye.

Here, for example, we've got dyer's weld, Roseda luteola.

This here for a red dye.

There's other dye plants here, like woad,

now being used as a treatment for cancer.

Now you've got dyes, you need something to dye.

Here, lots of plants used for their fibres.

We've got sisal, for example, for rope.

These are used in Japan.

And finally, one of the plants that changed the world, really. Cotton.

Hard to imagine the history of America being the same,

had it not been for the cultivation of cotton.

'Daniel Pretlove is one of the gardeners here at Chelsea.

'An aim of the garden is to keep it looking as it did in Miller's time.'

We still keep here, the vegetable beds, the herbal beds,

the pharmaceutical beds set out as Miller had them in his time.

They were reinstalled about 15 years ago.

He's a great person to have in your history, he's such a major figure in the history of English gardening.

He was here for such a long time. He changed the face of horticulture.

'Miller was an innovator.

'To grow the more exotic species he designed glasshouses

'with their own intricate heating systems.'

Miller had glasshouses. How did he heat them? They were coal-fired.

Did somebody have to stay up all night stoking the boilers?

They usually had someone.

Usually the under gardener, the apprentice, had to put out the fires.

Trainees today just don't know that they have such an easy time of it! That's right.

In his day, Philip Miller was regarded as the most distinguished

and influential gardener in Britain.

It wasn't simply for what he'd achieved at Chelsea.

It was for what he'd written.

Miller took the notes from the ill-fated Society of Gardeners

and compiled the first comprehensive dictionary of gardening.

Miller's book is this great bringing together of the knowledge of that time.

He's gathering together names and horticultural practice

and putting it in one place.

For the first time, everything you needed to know about every plant

found in an English garden was in one place.

It became the standard work, the bible, if you like.

Miller simply listed everything clearly and in alphabetical order.

He made no attempt to classify.

His dictionary, published in 1731,

became THE reference work for gardeners around the world.

All the names given to the same plant were listed together,

eliminating confusion.

The dictionary gathered more authority with every new edition.

And it turned Philip Miller into a superstar.

When you start on a new scientific venture

you must gather together all that is known about your subject.

That was Miller's great contribution.

His dictionary brought order and focus to all the knowledge available at that time.

His dictionary became an international best-seller.

This is what brought Carl Linnaeus to Chelsea Physic Garden in 1736.

Linnaeus wanted Miller to promote the sexual system of classification

by including it in the next edition of the famous dictionary.

But the meeting of the two egos was a frosty affair.

Linnaeus, we know, was an opinionated chap.

In Miller he had found his match.

Miller dismissed Linnaeus's classification system.

He predicted "that it will be of a very short duration".

Linnaeus had hoped for Miller's support.

Now he derided Miller's achievements as "mere plant collecting".

This was the beginning of a life-long rivalry.

So Linnaeus stared failure in the face,

but there was one chink of light for the self-styled prince of botanists.

Oxford.

Linnaeus came here,

to our botanic garden in Oxford, to see Johann Jacob Dillenius,

Professor of Botany.

He had read Linnaeus's book

and had not been convinced by it.

As Linnaeus demonstrated his vast knowledge of plants

and the beautiful simplicity of his sexual classification system,

the two became firm friends.

They were inseparable during Linnaeus's time in Oxford,

and they were to write to each other for the rest of their lives.

When Linnaeus left, Dillenius begged him under tears and kisses to live and die with him.

He offered to share his salary to keep him in Oxford.

Linnaeus had saved face. With the University of Oxford ready to accept his classification system,

he could return to Sweden with his head held high.

Who needed Philip Miller?

Linnaeus arrived back in Uppsala

with an ambitious plan to transform the Swedish economy.

His confidence in his own abilities knew no bounds.

However, he did raise sufficient funds

to establish a National Botanic Garden.

And this is the result, the botanic garden at Uppsala,

which Linnaeus had laid out according to his sexual system, as it still is today.

The plants are set out in beds

according to how many sexual parts they have.

I've wanted to visit Linnaeus's botanic garden for many years

and see his work first hand.

Coming to Linnaeus's garden is a pilgrimage for any botanist.

Seeing the plants laid out according to his sexual system

really is a testament to the genius of the man

and to his confidence that this was the system that people would adopt.

Just six years after his arrival in England as a penniless upstart,

Linnaeus was Professor of Botany at the university and the director of his own garden at Uppsala,

where he settled into a career of continued research and teaching.

Here he could have stood, master of all he surveyed.

'He had status, wealth and a crowd of adoring pupils

'who he used to take on lively botanical trails.

'The original Linnaean trails have been reintroduced

'by Dr Mariette Manktelow of Uppsala University.

'I joined her for a spot of botanising.'

He was a marvellous teacher. He was one of the best.

He was very charismatic and people loved to listen to him.

He really inspired his students.

These excursions,

they weren't the subdued botanising that you would expect? No.

They were fantastic. There could be 100 students... Amazing! ..singing.

They stopped at his house and everybody shouted,

"Hooray for Linnaeus!" They were very happy.

Word spread that this was how you learnt botany. Yeah.

He had hundreds of students coming with him in the 1740s.

'It was on these trails that Linnaeus identified a significant weakness with botany at the time.

'The names that were used for plants were very unwieldy.'

On one of the journeys he made to Stockholm he found this trifolium.

'For example, we came across this clover.

'Its name in Linnaeus's time was...'

Here we have one of those woodland plants that Linnaeus also saw here.

This is viola.

'For Linnaeus and his students, this viola's full title was...'

'These were descriptions of every minute detail of the plant.

'In this case, it translates as...'

'To teach, even just write down, these foot-long names had become completely impractical.'

How do you carry out field biology like this

if the name takes 30 seconds to say?

Linnaeus set out to find a neat and easy way for naming plants,

just as he thought he had found a neat and easy way of classifying them.

What Linnaeus realised was all a plant name had to do was designate.

It did not need to describe.

A universal language was needed to do this,

and that is what Linnaeus gave us.

He came up with a beautifully simple set of rules.

He reduced the lengthy names to just two words.

The first word is like a manufacturer's name.

The second word...

refers to the models of the things they make.

So, take...

..Becomes viola mirabilis.

Rather easier to remember. Much quicker to write down. Very simple.

Over the next two decades,

Linnaeus applied his two-name system to over 7,700 plants.

When he published them in his next best-seller, Species Plantarum,

it was a giant step forward for science.

Whereas Miller had listed all the names of every plant,

Linnaeus had come up with a system which was simple and short.

So this is a catalogue

of every plant name that has ever been used.

And each species has...

all the names that have been used plus Linnaeus's new name,

the short name, the two-word name.

This really sets the precedent for standardisation of names.

Without permanent names there can be no permanence of knowledge.

One after another, botanists and gardeners around the world

accepted the new two-name or binomial system, turning to Linnaeus

for the final decisions on what plants should be called.

With the exception, that is, of a certain Philip Miller.

Miller did not approve, railing instead, that Linnaeus had "the vanity of being the law-giver".

It was not until the eighth and last edition of Miller's dictionary

that Linnaeus's binomial system was finally included.

In his autobiography Linnaeus says

that he did not think that the binomial system would be his legacy,

but it was, and it's a big contribution.

In fact, it's a colossal contribution.

Thanks to Linnaeus, botanists around the world could now identify

and classify plants,

teach, correspond and advance their science easily,

efficiently, coherently.

Here in the botanic garden in Oxford, as elsewhere,

we still use Linnaeus's binomial system.

Some Linnaeus named after botanical heroes, thus immortalising them.

But for his arch rival Philip Miller

he had something else in mind.

For Philip Miller, Linnaeus spitefully chose

a rather weedy member of the daisy family.

Linnaeus believed there should be a connection

between the botanist and the plant.

The outer stumpy petals of the Milleria flowers reputedly refer

to Miller's plump figure.

Now, Linnaeus has a reputation for being arrogant and a self-publicist.

And yet the plant he chose to name after himself,

the twin flower, or Linnaea borealis,

is a sweet pretty little thing.

Perhaps Linnaea borealis is a very rare example of Linnaean modesty.

Maybe he was human after all.

Linnaeus's naming method was very successful and survives to this day.

The more botanists looked at his sexual system,

the more flawed it appeared.

There were inconsistencies and anomalies you can't have in science.

If you follow Linnaeus's system, you look at a lily,

it has six male parts, three female parts.

If you look at a yucca, it has six male parts, three female parts.

The same is true of butcher's broom. Same is true of asparagus.

Then you look at these plants, and they are so totally different.

The number of male and female parts can vary among different flowers

on the same plant.

It was not a reliable way to group plants.

Through his obsession with plant genitalia and perhaps his arrogance,

Linnaeus had ignored a fundamental flaw.

His mistake was to focus

on just one feature, the sexual organs of plants.

As John Ray had warned, any classification system has to take into account the whole plant.

As Linnaeus's system fell into disrepute,

botanists began to rediscover the work of the long-forgotten John Ray.

Amongst them was Philip Miller, who had the last laugh on his rival.

He had stood firm

against the juggernaut of Linnaeus's self-promotion.

Chelsea Physic Garden never embraced the sexual system of classification.

Without question, Miller was the outstanding gardener of his age,

but that doesn't mean he was popular.

Despite his fame, not a single portrait of Miller exists.

Not even a sketch. Why?

Because, like Linnaeus, he never underestimated his own ability,

and he suffered fools not at all.

So on his death, he left no friends to celebrate his achievements,

but he left plenty of enemies who would rather forget he ever existed.

The world of plants could be a brutal arena with colossal egos.

It could also be a dangerous place

if you wanted to push the boundaries.

Britain was still a God-fearing society.

The power of religious authorities remained a block on scientific advance.

If you were smart, you'd carry out experiments away from prying eyes.

OWL HOOTS

In 1716, a man called Thomas Fairchild

makes his way furtively to his garden.

He carefully closes the door of his potting shed and sets to work.

He wants to try an experiment that has never been done successfully.

Thomas Fairchild was a successful nursery man.

In Hoxton, north London, he sold not only British native species

but exotic plants

that people had sent him, but suppliers were unreliable.

He decided to take nature into his own hands.

Behind closed doors, Fairchild turned creator.

He wasn't interested in classification, and he didn't want to improve an existing flower.

He wanted to create a new plant

so that he could sell blooms that his rivals didn't have.

Fairchild was about to create an artificial hybrid flower,

a plant that couldn't be found in nature.

He had prepared two flowers, a carnation and a sweet william.

He took male pollen from the sweet william...

..and he placed it on the female part of the carnation.

And then, he waited.

He waited until the carnation produced seeds.

Then he sowed them. This was the true test.

When his hybrid seeds grew and burst into flower,

he knew he'd succeeded.

To dry and preserve his new plant,

he cut the stem of the ruffled pink bloom and pressed it carefully

between two sheets of paper.

And this is the result.

This simple specimen isn't much to look at,

but for botanists like me, it's a milestone -

the world's first scientifically created hybrid.

But when he finally emerged, clutching his sample,

it was not in triumph, but in dread.

Fairchild knew that most of his contemporaries

were still enthralled to the story of creation in the Bible.

God had made all the species of plant and animal, and that was that.

300 years ago, Thomas Fairchild

thought he had "created" a new species.

And his guilt was immense because he had cast doubt

on the story of the creation.

His reaction to assuage his guilt was to make a benefaction

to this church in Shoreditch so that an annual sermon could be preached

to glorify the work of creation.

He knew how important his discovery was.

He had made a new plant, and that should not have been possible.

He knew that man's relationship with plants would never be the same again.

It was nearly four years

before Fairchild dared tell the world about his experiment.

On 4 February 1720, he made his way anxiously to the headquarters of the Royal Society in London.

He presented his pressed flower to the scientific world, fearful of the reaction he might receive.

"The experiment by Mr Fairchild found a plant of a middle nature

"between a sweet william and a carnation flower,

"a specimen which produced no seed but is barren, like the mule."

These are the minutes of the meeting

when Fairchild came to the Royal Society.

He really didn't need to worry.

The members were able to see beyond the faded colours

of this now famous exhibit, and realise the significance.

The Fellows of the Royal Society were not so concerned with the Bible

as excited by the possibilities that the hybrid presented.

But there was a problem.

Fairchild's hybrid could not produce seeds.

It was sterile. Nobody knew why.

For all the progress, the steps towards classification,

and understanding the sex lives of plants,

to the first plant dictionary and a universal naming system,

still botanists could not answer this fundamental question.

Why was Fairchild's mule sterile?

What was the missing piece of the jigsaw

that would enable scientists to create fertile hybrids,

stronger crops, more efficient medicines?

The missing link was an understanding of how different plant species evolved.

This missing link arrived in the shape of Charles Darwin and his book on The Origin Of Species.

Botany was a passion of Darwin's.

He demonstrated that plants had the ability to adapt to surroundings

and, as a result, can increase their chances of survival.

He'd set sail in 1831 on board the HMS Beagle.

The ship's naturalist, he was fascinated by the diversity of plant life in the southern hemisphere.

Darwin saw that flowers which are pollinated by the wind

have little colour.

While those that need to attract insects are brightly coloured.

For over a decade, he observed plants and carried out experiments.

He understood that natural selection applied as much to plants

as it did to animals.

Darwin's theory of evolution, finally published in 1859,

may have put the cat amongst the pigeons in religious circles.

But for botanists, it was like manna from heaven, finding the Holy Grail, because it explained everything.

19th-century botanists recognised the significance of Darwin's work

on how and why plants evolved into different groups.

In his notes for the book,

Darwin uses this illustration.

It's the metaphor of a tree,

showing how species diverged as they evolved.

Growing from a central trunk, some branches dying out,

others sprouting further growth.

The newest twigs and leaves far away from the roots but still connected.

The Origin Of Species changed everything.

Darwin explained why we CAN classify plants.

The plants in a well-defined natural group share a common ancestor.

He explained why plants with fewer things in common

are more distantly related,

and why plants that have a lot in common are more likely to produce fertile offspring.

Botanists now understood

why Fairchild's experiment 150 years earlier had failed.

The plant he bred was sterile

because the carnation and the sweet william

come from two distinct species.

They're not closely related enough to breed successfully.

This understanding of the importance of classification

underpins botanical science to this day.

I've come to probably the most famous botanic garden in the world, Kew Gardens.

It's where I trained as a gardener.

The work begun by Miller, Linnaeus, Fairchild and John Ray

continues here.

Simple field lenses are supplemented by 21st-century tools

such as scanning electron microscopes and DNA analysis.

The work to define and classify plants

is as vital as ever.

One of the scientists, Professor Monique Simmonds,

came across a plant in Ghana that was being used to treat malaria.

She was curious to see if there was scientific basis for the treatment.

The plant belongs to the same family as sage.

The herbarium archive at Kew found 300 species in the same group,

62 of which have also been used in traditional medicines.

Professor Simmonds identified her specimen

as Plectranthus barbatus...

..and began a chemical analysis.

She found a totally new anti-malarial compound.

The active compounds that we're looking at appear to be in the hairs on the leaves.

Right. And when you stress the plant, when you cut it back,

the leaves that then regrow

seem to have a higher concentration of the active compounds.

That was encouraging, but was Plectranthus barbatus

the best source of the anti-malarial compound?

Could other related species produce more of the compound

or a more potent version?

Before we develop the project, we want to make sure that we've got the most effective species.

If you look at the plants around us here, are the ones that are similar related,

or are the ones that are diverse in style related?

Molecular data can give us an insight into one species and its "near neighbours".

Near neighbours most likely share a similar type of chemistry.

The molecular data is the DNA fingerprinting?

The DNA fingerprinting is what we're using as molecular data.

The leaves of the Plectranthus are ground in a pestle and mortar,

dipped in a hot bath mixed with chloroform, then shaken and spun.

The sediment is removed, and when ethanol is added

strands of DNA are visible, even to the naked eye.

The sample is then frozen, along with another 40,000

that make up an extraordinary database at Kew.

By comparing this DNA with that of other species of Plectranthus,

Professor Simmonds and the team came up with a precise family tree

showing the nearest relatives to her original specimen.

The DNA tree has enabled us to identify four or five other species

that might contain similar or more active compounds,

and that's the exciting part of the project.

That's what we're putting our efforts into.

We'd really like to find a new anti-malarial

that could serve as a platform for development of a new drug.

That would really be exciting.

The malaria project demonstrates how valuable it is to understand the connections between plants.

Incredible to think how far we've come since the early pioneers.

Ray, with his hand lens, could only study plants from the outside.

Now, with modern equipment, we can look from the inside outwards.

The ability to harness and manipulate plants

was made possible by the classification of the plant kingdom.

The importance of botany and those early pioneers cannot be overstated.

I know you'd expect me to say that, but it's true.

'Next time on Botany: A Blooming History,

'I'll look at how botanists wrestled with the question

'of what plants do with water, sunlight and carbon dioxide,

'the amazing process known as photosynthesis.'

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