The type of germination in which the cotyledons remain below the soil surface is

Hypogeal germination is the type of seed germination in which the cotyledons remain below the soil surface. During hypogeal germination, the epicotyl (the part of the embryonic axis above the cotyledon attachment point) elongates and pushes the plumule (young shoot) upward through the soil, while the hypocotyl (the part below the cotyledon attachment) does not elongate significantly. As a result, the cotyledons stay underground, where they continue to supply stored food to the developing seedling until it becomes self-sufficient through photosynthesis. Examples include maize, rice, mango, and most monocots.

In epigeal germination, the hypocotyl elongates rapidly, pulling the cotyledons above the soil surface, where they may turn green and photosynthesise temporarily. Examples include beans and groundnuts.

The plumule is the embryonic shoot, not a type of germination. The micropyle is the tiny pore in the seed coat through which water enters during imbibition, not a germination type.