Hilum (biology)

In botany, a hilum (pronounced /ˈhaɪləm/) is a scar or mark left on a seed coat by the former attachment to the ovary wall or to the funiculus (which in turn attaches to the ovary wall).^[1][2] It is commonly known as the "eye" in some bean and pea species.

The hilum is the white region in the center of the namesake "black eye" of the black-eyed pea

For some species of fungus, the hilum is the microscopic indentation left on a spore when it separates from the sterigma of the basidium.^[3]

A hilum can also be a nucleus of a starch grain; the point around which layers of starch are deposited.^{[citation needed]}

The adjectival form hilar denotes the presence of such a mark, and for some species it can be used as a distinguishing characteristic.^[2]