Begonia

Begonias were a type of flowers found on Earth.

In 1963 the Eighth Doctor bought a begonia from Fitz Kreiner. (EDA: The Taint)

In 1964, Rachel Jensen took up raising begonias after retiring. (DW: Remembrance of the Daleks, MA: Who Killed Kennedy)

Begonias went extinct before the 26th century, but seeds were preserved on a secret base on the Moon. Bernice Summerfield found the base and took the seeds, giving them to Professor Sabron Jones to grow in his gardens on Dellah. (BNA: The Mary-Sue Extrusion)