Absorb endosperm energy through a single cotyledon, known as the scutellum. The radicle is enclosed within a coleorhiza at one end of the embryo, an the epicotyl and first leaves or plumule are enclosed within a coleoptile at the other end. These structures serve to protect the delicate developing root and shoot. When the seed coat splits, the radicle forms a primary or seminal root that penetrates through the coleorhiza. The coleoptile grows up above the soil surface, and this splits to allow the first true leaves to emerge. The endosperm remains in the seed coat and below the ground to fuel this early development, until the first true leaf begins photosynthesis and energy production. In other monocots, a hooked cotyledon emerges above ground with the endosperm and seed coat still attached (onion or lily). This is superficially similar to gymnosperms, and to one kind of dicotyledonous emergence.