Oak

Oak trees were plants native to Earth. The Fourth Doctor claimed that oak trees don't grow anywhere else in the galaxy. (DW: The Android Invasion)

For thousands of years, the Centuripedes used the oak trees of Earth to build pods to transport their eggs. (K9TV: The Last Oak Tree)

In the 12th century, an oak tree known as Major Oak was used by Robin Hood and his merry men as their sanctuary. (K9TV: The Last Oak Tree)

Some time before the 18th century, an Ambition Parasite came from Esto to Earth and infested an oak tree. (WC: Number 1, Gallows Gate Road)

In the 1970s, Styggron's replica of Devesham included fake oak trees. (DW: The Android Invasion)

By 2050, oak trees were extinct (at least in England), having been all cut down or died of pollution. The last oak tree, Major Oak, was kept on display in a museum in London. This tree was stolen by a Centuripede and used to build a pod for her eggs. After Starkey and K9 helped save her eggs from Drake's bomb, she rewarded them by saving their lives and giving them the acorns she had saved from Robin Hood's time. (K9TV: The Last Oak Tree)

Anzor's TARDIS once took the form of an oak tree. (BFA: Mission to Magnus)