Phylox

Phylox was a star system located in the Andromeda Galaxy. The Wirrn devastated the Phylox system, possibly meaning that Phylox was part of the Wirrn Breeding Colonies. (EDA: Placebo Effect)

As part of a trap set for the newly-regenerated Fifth Doctor, the Master created the city of Castrovalva on a planet in the Phylox series. (DW: Castrovalva)


 * The different uses of "system" and "series" could just be a writing error in the storyline.