• (n.) A sheath in the embryo of grasses, inclosing the caulicle.
(from the article `plant development`) ...The scutellum arises from octant cells, which also contribute to the cotyledon. The basal cell forms part of the coleoptile and also gives rise to ...
<plant biology> Closed hollow cylinder or sheath of leaf like tissue surrounding and protecting the radicle (young root) in grass seedlings. ... (18 Nov 1997) ... 
Co`le·o·rhi'za noun [ New Latin , from Greek ... sheath + ... root.] A sheath in the embryo of grasses, inclosing the caulicle. Gray. 
coleorhiza (s), coleorhizae (pl) A sheath of tissue that surrounds the radicle in a grass plant embryo.
the sheath that envelops the radicle in certain plants and that is penetrated by the root in germination.