Hypogeal germination is a type of seed germination where the cotyledons (seed leaves) remain below the soil surface. This occurs because the epicotyl (the embryonic axis above the cotyledons) elongates rapidly, pushing the plumule (the embryonic shoot) above the ground while keeping the cotyledons buried. Common examples of plants with hypogeal germination include peas, maize, and mangoes.

A. plumule is not a type of germination but a part of the plant embryo that develops into the shoot system.

B. micropyle is a small pore in the seed coat through which water and oxygen enter the seed to trigger germination.

D. epigeal: In this type of germination, the hypocotyl elongates rapidly, pushing the cotyledons above the soil surface where they often become photosynthetic. This is common in plants like beans and sunflowers.