🚀 go-pugleaf

Hello,
can anybody tell me what the "nut" inside a ginkgo seed is produced
from?

The outer fleshy layer is the sarkotesta, the stony middle layer the
sklerotesta and the third is dry and papery (is there a special name for
it?). All three of them are build up by the integument (if my
information is right).

But what is the "nut inside". If I am right, the egg cells are sometimes
fertilised when the seed has already fallen to the ground. So the "nut"
can not be the embryo. But what is it, and why can an egg cell be
fertilised and develop the embryo when the seed has already fallen to
the ground?

Ginkgo is a fascinating Gymnosperm plant but some things are hard to
understand.
Anybody can help me?
Matthias

e-mail: MKlein@uni-bonn.de