Astride a lumbering elephant, Dr Colin Pendry ducked to avoid the branches of a towering dipterocarp tree as his party made slow progress along the banks of the River Rapti.

In the steamy lowland jungle of the Royal Chitwan National Park in Nepal, fending off mosquitoes, the Edinburgh botanist was hunting for rare and interesting specimens, including the sub-tropical Bischofia tree.

But Pendry and his party were not the only creatures on the prowl. “We certainly saw a rhino and there were tracks made by leopards and tigers,” he says with no hint of anxiety in his voice now — whatever his emotions at the time.

Back in the relative safety of the Royal Botanic Garden Edinburgh (RBGE), recalling their adventures, Pendry and his colleague, Mark Watson, make modest heroes. The pair have just returned from the latest leg of a 15-year project, following in the footsteps of Victorian plant-hunters in an attempt to help preserve some of the world’s most endangered species.

Dressed casually in sweaters and chinos, they scoff at any notion that they have achieved the status of some real life Indiana Jones. Yet, like the Jones of fiction, a fair chunk of their working lives is spent dodging landmines, carefully circumnavigating man-eating tigers and trekking at lung-bursting altitudes.

“It all seems pretty safe to us, and no, my girlfriend doesn’t worry about me when I’m gone,” insists 41-year-old Pendry.

Their latest three-week trip took the experts to Kathmandu, the heaving capital of Nepal in the heart of the Himalayas. With funding from the government’s Darwin Initiative, the aim is to create an official record of the area’s rich plant environment, which would prove an invaluable aid for conservationists.

Existing checklists for the region, recognised as one of the world’s top 20 global biodiversity hot spots, record around 7,000 species of flowering plants and ferns. The UK, by comparison, has fewer than 2,000 species.

The need for such data grows ever more pressing because many of these species are on the verge of extinction. Their last field trip was to a forest in the Kathmandu valley, a bumpy 20-minute ride from the capital in a clapped-out coach. There, looking out onto the snowy Himalayan peaks, the team walked among evergreen oaks, chestnut trees and rhododendrons, collecting specimens.

It might sound like a stroll in the park but the unstable political situation in Nepal means that danger is never far away. Last February, the king dismissed the government and assumed overall control of the country. Faced with growing unrest and political demonstrations that bring the region to a standstill, an understandably nervous army does not take too kindly to strangers, especially when collapsible tree pruners in a rucksack look uncannily like guns. “We’ve got to be very careful of that,” says Pendry.

A century ago, a plant hunter’s lot was even less of a picnic. George Forrest was forced to flee for his life from Tibetan warrior priests who murdered two of his missionary friends in 1904. Disguised as a local, he hid in the hills for 21 days. “About 20 natives were killed and a great many more captured and taken into slavery,” he wrote. The attack resulted in the loss of 770 specimens and seeds, plus his camera and negatives — a whole season’s work.

Thanks to explorers like Forrest and Francis Buchanan-Hamilton, who was the first person to collect plants in Nepal, thousands of specimens are preserved in the RBGE herbarium, a legacy that has introduced botanists to a rich and unique flora and changed the look of gardens across the country. We owe many now familiar species of Primula, Rhododendron, many conifers and other plants to the exploits of these men and others like them.

“I think it’s incredible that they did what they did,” says Pendry. “We grouse about the hardships of a five-week trip but they were away for a year or two years at a time facing a lot more hardship than we ever would. They are the pioneers. We are following in their footsteps,” says Pendry.

Pendry and Watson have completed three expeditions to remote areas of Nepal, two to the high mountains of the Everest region in Sagarmatha National Park and one to the Royal Chitwan National Park.

In Sagarmatha National Park, yaks stumble along paths first made by locals centuries before. With Sherpas helping guide the way, the botanists collect specimens amid alpine woods, Rhododendron and junipers.

After a day of arduous trekking, evenings are spent in makeshift tents as temperatures fall to just above freezing. A small generator provides electricity, allowing the team to power computers and recharge batteries for digital cameras. “Unfortunately, there’s no sitting round a campfire,” says Pendry. Cutting down trees is too damaging to the environment.

With gardening second only to reading in terms of our favourite leisure pursuits, the work of people like Buchanan-Hamilton live on in gardens across Scotland. Thanks to the efforts of botanists such as Pendry and Watson, his legacy will also live on in Nepal.

For more information on the Royal Botanic Garden Edinburgh visit www.rbge.org.uk

Times Recommends

• UK regional accents thrive against the odds
• ‘Scarecrow’ wind farms put rare birds to flight
• What an anti-climax: G-spot is a myth