Silverleaf palm tree

Silverleaf palm trees were found around Cartago, a domed off-world colony of the Homeworld. When the Monk was teaching the Corsair how to fence, they used silverleaf trees as targets. The fronds of these trees were sturdy and flexible enough to be folded into novelty bowties, and the Monk once decided to give one to the Colonel. (PROSE: The Bloodletters)

Behind the scenes
On many occasions, Gallifreyan trees have been mentioned to have silver-coloured leaves, suggesting the silverleaf palm trees may have been imported by the Homeworlders to Cartago instead of being native to the planet.