Next time you order a coffee from any of the major chains bear in mind that no matter which you choose, whether it's Columbian, Kenyan or even Hawaiian, you will still only be drinking one of the 120 species in the world.

This diverting fact, and many more like it, will be revealed in a new documentary starting on Radio 4 next week entitled Plants: From Roots to Riches.

The 25-part series was recorded over many weeks at the Royal Botanical Gardens at Kew and not only features interviews with many of its scientists and botanists, but is also being presented by its top professor.

Last night (Tuesday) the gardens' director Richard Deverell joined with Radio 4's controller Gwyneth Williams to officially launch the documentary in the stunning surroundings of the Princess of Wales Conservatory.

Mr Deverell said: "We are delighted to be part of this exciting project. Public service broadcasting really really matters because it provides an incredible insight into the world and results in more informed citizens.

"It fuels debate and often sparks a life long interest and passion in subjects you did not realise previously you were interested in.

"In this documentary will be featured incredible stories; like the early plant hunters who risked life and limb to bring back various species to this country.

"This is also a hugely contemporary issue as it is now estimated that just 12 types of plant provide 80 per cent of the calories consumed by humans.

"In my lifetime there will be an additional three million people in this world, how are we going to feed them all?

"This series is timely, it is revelatory and it is relevant."

Mr Deverell also revealed a book would be coming out to support the series and that it would be produced by John Murray, the same publishing firm which in 1859 published On the Origin of Species by the famous naturalist Charles Darwin.

The history of water lilies like this will be one of the subjects featured on Plants: From Roots to Riches on Radio 4
 

Ms Williams also thanked all of the contributors to the documentary and said: "We have a very discerning and discriminating audience and I can tell that they are going to love this series.

"I was very interested to learn from it that one of the oldest pot plants in the world is the rare Snake Plant (Sansevieria Trifasciata) the seeds of which are gathered from my home country of South Africa.

"I hope that we will carry the research done here across the boundary and make science a much greater part of the Radio 4 fayre we provide listeners."

The oldest pot plant in the world is a cycad called Encephalartos altensteinii which also happens to have a home at Kew - within the grand Palm House - and will feature in the opening episode.

Professor Kathy Willis, is director of science at Kew and also will present the documentary.

As well as highlighting the fact about coffee species, she explained how attempts to grow the first rubber trees outside their native Brazil were made in 1875 when Henry Wickham smuggled some 70,000 seeds to Kew - four per cent of which germinated successfully and were sent to Ceylon (Sri Lanka) and Singapore leading to the global production of rubber which literally changed the world and industry.

She added: "With 250 years worth of research you obviously can't cover everything, but it's been a wonderful eight months putting this documentary together.

"While much has changed in that time, what hasn't changed is our love of plants and the vital part they play in all our lives.

"I hope everyone enjoys the series as much as we did."

The series begins this Monday (21) at 1.45pm

Tonight (Wednesday) also sees the start of the annual Kew the Music festival at the gardens.

Songsmith Elvis Costello will kick things off at 7.30pm with music drawn from his 35 years as a musician. He will be followed tomorrow by ABBA tribute act Bjorn Again,and on Friday by Jools Holland and his Rhythm and Blues Orchestra featuring support from Soft Cell's Marc Almond and Melanie C from the Spice Girls.

The weather is expected to get hotter and hotter over these three nights before severe thunderstorms are predicted to potentially overshadow Saturday's sold out performance by the legendary Simple Minds.

There may also be the odd shower on Sunday when funny man Bill Bailey takes to the stage with support from the chirpy cockneys Chas and Dave.

For information and any tickets still on sale visit the official website.

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