Sphereosis was a plant whose name meant "that which feeds from underneath". The Tenth Doctor encountered it on Earth in the far future. He said it had been growing underground for billions of years after it had landed. It could speak in English but found it difficult. It said it 'started to grow, taking life and nutrients sending out its roots and feelers and tubers', slowly altering its genetic structure until it could walk. The Doctor found it fascinating and one of the first things he asked it was its name. When it replied, it said it did not know. The Doctor asked it what Karl Baring would call it and it said Sphereosis. (AUDIO: The Day of the Troll)