Definitions for "Hypogeal"
Plants in which the cotyledons remain below the surface of the soil.
of germination, having the cotyledon(s) remaining within the seed coat. cf. epigeal.
The germination is hypogeal when the cotyledons will remain under the soil surface. Usually the cotyledons will stay inside the seedcoat. Examples : Araucaria, Cephalotaxus - partially, Ginkgo, Keteleeria, Torreya.
Keywords:  underground, means
Hypogeal means "underground".