The truffle, Tuber cibarium, which grows in the soil, and produces its spores within tuber-like bodies.(noun)
The Century Dictionary (Public Domain)
Use "earth-ball" in a sentence
"Ladies did not disdain those pagan ironed times of the firs; city (called after the ugliest Danadune) when a frond was a friend inneed to carry, as earwigs do their dead, their soil to the earth-ball where indeeth we shall calm decline, our legacy unknown."
"The upper part of the earth-ball should be level or slightly deeper than the edge of the hole."
"Be sure not to break the earth-ball when setting the seedling into the planting hole."