Janet Baraclough wrote:

The message
from "Bob Hobden" contains these words:
I also don't think it a seed because of the well distributed roots, more
like a garlic, leek or perhaps lilly "pip or bulbil" that's rooted.

It looks to me like a very small green potato; or possibly a
potato-plant fruit.

The 'well distributed roots' thing can happen to an avocado or a seed
if it wasn't burried and just laid on a waterlogged ground and took
hold with its roots without rotting. A stressed seed sends roots all
over the place in those conditions. Also too large for farlic, leek or
pip or bulbil.

It is too round, too perfect a shape and has a basal eye right at the
centre suggesting it had a flower then a fruit, so it's not a potato.

I'll go with the avocado suggestion.