A rare orchid thought to be extinct in the UK was found growing on a London bank's rooftop garden

• A rare orchid thought to be extinct in the wild in the UK was found in June atop a bank in London.
• The Small Flowered Tongue Orchid - Serapis parviflora - had not been seen in the UK since 2009.
• The flowers are typically found in the Mediterranean basin and Atlantic coast of France, Spain, and Portugal, the BBC said.

Rare orchids that were believed to be extinct in the UK were found growing on the rooftop of a bank in London.

According to Nomura International, the 15-strong colony of Small Flowered Tongue Orchid - scientific name Serapis parviflora - was found growing on the 11th-floor rooftop on June 4.

The last known colony of these flowers in the UK was found in Cornwall in 1989, Nomura said in the press release, but those flowers were destroyed in 2009.

It's not exactly clear how the rare flowers ended up atop the London building.

"Orchid seeds are incredibly small and can travel great distances by wind," said Nomura ecologist Mark Patterson, who oversees the garden. "The plants could have originated on the Continent and been brought over the Channel on southerly winds which frequently bring Saharan dust deposits to the capital."

"Once settled on the Nomura roof, the seeds would have formed a symbiosis with a mycorrhizal fungus enabling them to germinate and grow," he added, saying the odds of such an unlikely event were "astronomical."

Patterson also said the seeds could have been present in the soil that was brought to the roof when the garden was first created about a decade ago.

The flowers typically found in the Mediterranean basin and Atlantic coast of France, Spain, and Portugal, according to a report from the BBC. The orchids flower for just a few weeks at a time, according to the report.

The hot and dry conditions on the London rooftop likely helped the flowers grow because they created a condition more typical of their native habitat, the BBC reported.