Hypogeal germination - a form of seed germination in which the cotyledon/cotyledons (seed leaf/leaves) remain below the soils surface and the coleoptile (hollow tube through which the first true monocot leaves emerge)/plumule (embryonic shoot) emerges above the soil surface without the cotyledons to produce the first true leaves.

Epigeal germination - a form of seed germination in which the seed, along with the cotyledon/cotyledons and plumule, is pushed above the soils surface. The first true leaves are produced at the tip of the growing shoot above the cotyledons.

Cleistogeal germination - a form of seed germination, found in the case of some tropical plants, in which a special umbrella-like leaf on a stalk forms above the ground and protects the plumule from damage. The cotyledons remain below the soil surface as in the case of hypogeal germination. The plumule emerges only after substantial development.

Wow, thanks a lot Brandon! Beautiful explanation.
Regards. Paul.