- "Don't be a fool. Those things are like gems."
- ―Jet, on the seeds of the Grey Ash[src]
The Grey Ash is a species of cactus that is highly prized for its use in curing Venus Sickness. It is also very hard to grow, and does not survive in thick atmospheres with helium, such as Venus. The plant withers immediately on exposure.
Based on what we see in the anime, the Grey Ash would probably not belong to genus Coryphantha, as it lacks the characteristic tubercles of such cacti in our world.