A leading UK horticulturist has revealed her "top 10" plants that have changed humanity.
The list, which includes cannabis, the opium poppy, rice, cotton and rubber as well as some unexpected candidates such as the yam, tulip and quinine plant, was unveiled by Sue Minter, director of horticulture at the Eden Project in Cornwall at the Bord Bia sponsored David Robinson Memorial Lecture at the Salesian College of Horticulture in Drumree, Co Meath, last night.
A small handful of plants have changed the world, sometimes for good and sometimes for ill. One enabled the British Empire to spread round the world.
Another changed the status of women, allowing them to take control of their fertility.
"The number of plants that have influenced humankind is huge," Ms Minter told The Irish Times before the lecture.
"I was asked to sit down and think of the 10 plants of most importance to humankind. It is partly a brain teaser."
When considering which plants to include she took into account the positive and negative impacts on humanity, their common point being a major influence on the course of human history.
Top of her list is the opium poppy, Papaver somniferum. "If I had to nominate one plant for its maximum positive and maximum negative impact on humanity I would choose this plant," she said.
It is the source of "untold human misery through heroin addiction", but is also vital as pharmaceutical morphine in the treatment of cancer. No cancer ward would wish to be without it "since it rids the body of extreme pain like no other substance on earth".
Her second most important is the yam, Dioscorea mexicana, the original source for the contraceptive pill. "It was discovered back in the 50s in Mexico." It changed the status of women worldwide, she said, allowing them to control their fertility. The yam "transformed the lives of women from the 60s onward", Ms Minter said.
She placed tobacco, "the evil weed" in seventh place. "It has a massive impact on health, but also has a Janus face as a very useful plant for drug and vaccine development. It is a laboratory rat sort of plant." It could come into play to produce vaccines against Sars and avian flu, she added.
Next in descending order is the South American Cinchona tree, the bark of which provides the anti-malarial drug quinine. It has prevented millions of deaths but also supported empire building. "I don't believe there would have been a British Empire without quinine," she said. "It literally enabled the British to colonise, with all the implications that had."
She includes rice rather than wheat next on her list, as a key food source. "Rice provides more than 80 per cent of the nutritional requirements of over 50 per cent of the world's population," Ms Minter said.
Rubber comes next because its processing into tyres greatly contributed to the car culture "with all its attendant problems of pollution, global warming and urban congestion".
Cotton is there, given its social and cultural impacts. "It has had such an effect on the slave trade and is right up to date in remaining controversial given the GM [genetically modified] varieties being grown." It also has environmental impacts as a third of the world's pesticides are used in the cotton industry.
The hemp plant, Cannabis sativa, is included not just as a drug, but because it was a crop fundamental to the Elizabethan economy in England. The fibres it produced clothed people, provided sailcloth and rope for the navy and was so essential that you could be fined for not growing it, Ms Minter said.
Tea is ninth on the list and is important as a world industry. From its home in China, tea as a crop has spread around the world.
The tulip lies tenth on her list. Attempts to acquire its bulbs developed into a spending frenzy in the Netherlands between 1634 and 1637, driving up prices well above that for gold. "The plant created the world's first futures market," as people awaited new colours, she explained.
SEEDS OF CHANGE: plants that transformed mankind for better or worse
1. Opium poppy
Essential for the pain killing cancer drug morphine, but infamous as the source of heroin and the addiction it causes.It drove the Anglo-Sino Opium Wars in the mid-1800s where opium addiction was promoted to gain commercial trading advantages.
2. Yam
Its ability to block conception in otherwise fertile women was first noted in Mexican women in the 1950s. An active ingredient was synthesised to deliver the birth control pill, transforming the lives of women who became free from the burden of fertility.
3. Tobacco
It is a direct cause of death from heart disease and cancer among those who smoke and those living with smokers.
It is valuable in the laboratory however, because it is easily genetically engineered to produce human vaccines and drugs.
4. Quinine
Recovered from the bark of the Cinchona tree, this anti-malarial drug has saved countless lives from a disease that remains the world's number one killer. It also allowed British armies to establish colonies in tropical countries around the globe.
5. Rice
It is the main source of nutrition for more than half the world's population. Its cultivation has also transformed landscapes in southeast Asia where it is cultivated intensively. Genetically engineered varieties may further boost its importance.
6. Rubber
Rubber tyres allowed the motor industry to develop, bringing with it pollution and fuel crises. Natural rubber is still widely used today in medical appliances and a form of blood serum, albumen, can be manufactured from rubber latex.
7. Cotton
The labour intensive nature of cotton production drove the slave trade in the southern US, with all its suffering and legacy in current race relations.
Cotton also indirectly causes pollution, given a third of the world's pesticides are used in its cultivation.
8. Cannabis
Also known as hemp, its fibres were a key raw material for clothing and rope in 16th century Britain. A class II narcotic, the cannabinoid drugs it contains may provide important medical treatments for conditions from multiple sclerosis to cancer.
9. Tea
Originally from China, tea was introduced to the Himalayas by the East India Company's Robert Fortune. Originally much scarcer and more valuable than today, it is now grown around the world and remains one of the world's most popular drinks.
10. Tulips
The flower and its bulbs are major export crops for Dutch growers and also help support tourism. Such was the demand for tulips that they cost more by weight than gold and a bulb futures market developed.