The world's largest plant has been discovered, researchers say

The world's biggest plant has been discovered, researchers from The University of Western Australia and Flinders University say. The plant, "an ancient and incredibly resilient seagrass," stretches 111.847 miles and is at least 4,500 years old, according to a news release.

The plant was discovered in Shark Bay in Western Australia, when researchers were trying to determine which plants should be collected for seagrass restoration.

"We often get asked how many different plants are growing in seagrass meadows and this time we used genetic tools to answer it," said Elizabeth Sinclair with the UWA Oceans Institute, a senior author of the study and a professor in UWA's School of Biological Sciences.

The researchers sampled seagrass shoots from across Shark Bay and realized the shoots all came from just one plant, not multiple. "The answer blew us away – there was just one!" said UWA student researcher Jane Edgeloe, lead author of the study. "That's it, just one plant has expanded over 180km (111 miles) in Shark Bay, making it the largest known plant on earth."

The underwater meadow appears to have expanded from a single seedling, she said. 

Sinclair said the plant is unique in that it is a polyploid, meaning the seedling contains 100% of the genome from each parent, rather than sharing the usual 50%.

"Even without successful flowering and seed production, it appears to be really resilient, experiencing a wide range of temperatures and salinities plus extreme high light conditions, which together would typically be highly stressful for most plants," Sinclair said. 

The researchers are now doing experiments in Shark Bay to understand how this plant survives and thrives under such variable conditions.