In botany, a hilum (pronounced ) is a scar or mark left on a

seed coat A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiosperm p ...

by the former attachment to the ovary wall or to the funiculus (which in turn attaches to the ovary wall). On a bean seed, the hilum is called the "eye". For some species of

fungus A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from t ...

, the hilum is the microscopic indentation left on a spore when it separates from the

sterigma In biology, a sterigma (pl. sterigmata) is a small supporting structure. It commonly refers to an extension of the basidium (the spore-bearing cells) consisting of a basal filamentous part and a slender projection which carries a spore at the ti ...

of the

basidium A basidium () is a microscopic sporangium (a spore-producing structure) found on the hymenophore of fruiting bodies of basidiomycete fungi which are also called tertiary mycelium, developed from secondary mycelium. Tertiary mycelium is hig ...

. A hilum can also be a nucleus of a starch grain; the point around which layers of starch are deposited. The adjectival form ''hilar'' denotes the presence of such a mark, and can be used as a distinguishing characteristic of a

seed A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiospe ...

or spore.

References

{{Reflist Plant anatomy Fungal morphology and anatomy