The embryo develops at the micropylar end of the embryo sac where the zygote is situated.
The zygote gives rise first to the pro-embryo, and then to the globular, heart-shaped, mature embryo.
A typical dicot embryo consists of an embryonal axis and two cotyledons.
The portion of the embryonal axis above the level of cotyledons is called epicotyl.
It contains the plumule (shoot tip).
The portion below the axis is called hypocotyl.
It contains the radicle (root tip). The root tip is covered by the root cap.
In a monocot embryo, there is only one cotyledon. In grass, it is known as the scutellum, and is situated at one side of the embryonal axis.
At its lower end, the embryonal axis has the radicle and the root cap enclosed in the coleorrhiza.
The epicotyl lies above the level of the scutellum, and has the shoot apex and leaf primordia enclosed in hollow structures called coleoptiles.
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