Genetic testing has determined a single 4,500-year-old seagrass may have spread over 200 sq km of underwater seafloor – about 20,000 football fields

About 4,500 years ago, a single seed – spawned from two different seagrass species – found itself nestled in a favourable spot somewhere in what is now known as Shark Bay, just off Australia’s west coast, the Guardian reports.

Left to its own devices and relatively undisturbed by human hands, scientists have discovered that seed has grown to what is now believed to be the biggest plant anywhere on Earth, covering about 200 sq km (77 sq miles, or about 20,000 rugby fields, or just over three times the size of Manhattan island).

The species – a Posidonia australis, also known as fibre-ball weed or ribbon weed – is commonly found along the southern coastlines of Australia.

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