Epigeal germination: During seed germination, the cotyledons are brought above the ground due to the elongation of hypocotyl. This type of germination is seen in many dicotyledonous like sunflower, castor, bean, onion etc. Here the cotyledons, besides food storage, also perform photosynthesis till the seedling becomes independent. In some other plants like bean, the cotyledons being thick, do not become leaf-like; they shrivel and fall off after their food reserves are consumed by the seedling.