Monocot seeds are endospermic but in some as in orchids seeds are non endospermic. In some monocots like castor and maize the cotyledons are thin and membranous. In such seeds food is stored in the endosperm. Cotyledons act as absorbing organs. They absorb food from the endosperm and supply to the growing embryo during seed germination.
The seed has a seedcoat, the biggest portion of the seed is the endosperm and smaller portion is the embryo both are separated by protein layer called Aleurone layer which is surrounded to the endosperm. The endosperm is the food storing tissue rich in starch.
The embryo lies on one side of the endosperm and consists of a single shield shaped cotyledon known as the scutellum. The scutellum, which is in close contact with the endosperm absorb food material from it during embryo development. The embryonal axis has the upper portion, the plumule with minute leaves and the lower portion is the radicle. The plumule is surrounded by a plumule sheath called coleoptile and the radicle is surrounded by a root sheath called coleorhiza.
