Ryos was a planet generally ignored by space travellers and dismissed as an ugly wasteland.
Its geology was distinguished by massive hoodoos which were connected to each other through narrow natural stone bridges. Native species included the Ryosians who lived on the high plateaus and a large domesticated beast of burden. Few plants have been observed but the Ryosians built thatch huts, indicating the presence of some kind of grass or rush.
In the 82nd century, a medic crashed on the planet and both the Doctor and Keepsake came in answer to her distress signal. (DWM: Keepsake)
Location
Keepsake's ship was able to travel from Ryos to Earth, despite the ship's age and technical faults, indicating it was likely in Mutter's Spiral. (DH: Don't Forsake Me Oh My Darling!)