nucellus

American  

[noo-sel-uhs, nyoo-] / nuˈsɛl əs, nyu- /

noun

Botany.

plural

nucelli

1. the central cellular mass of the body of the ovule, containing the embryo sac.

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nucellus British  

/ njuːˈsɛləs /

noun

1. the central part of a plant ovule containing the embryo sac

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nucellus Scientific  

/ no̅o̅-sĕl′əs /

plural

nucelli

1. The megasporangium of a seed-bearing plant, located in the ovule. In angiosperms, it is the central portion of the ovule in which the embryo sac develops. In some cases of apomixis (production of seeds without fertilization), cells of the nucellus develop into an embryo.

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Other Word Forms

• nucellar adjective

Etymology

Origin of nucellus

1880–85; < New Latin, equivalent to Latin nuc- (stem of nux ) nut + -ella -elle

Example Sentences

The embryo-sac enlarges greatly, displacing gradually the surrounding nucellus, which eventually forms merely a thin layer around the sac, or completely disappears.

From Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 3 "Frost" to "Fyzabad" by Various

The plants included are, however, mainly well-established parasites, and the absence of nucellus is only one of those characters of reduction to which parasites are liable.

From Encyclopaedia Britannica, 11th Edition, Volume 2, Part 1, Slice 1 by Various

The integuments do not completely invest the apex of the nucellus, but an opening termed the micropyle is left.

From Encyclopaedia Britannica, 11th Edition, Volume 10, Slice 5 "Fleury, Claude" to "Foraker" by Various

A papery remnant of nucellus lines the inner face of the woody shell, and, as in cycadean seeds, the apical portion is readily separated as a cap covering the summit of the endosperm.

From Encyclopaedia Britannica, 11th Edition, Volume 12, Slice 7 "Gyantse" to "Hallel" by Various

In Araucaria and Saxegothaea the nucellus itself projects beyond the open micropyle and receives the pollen-grains direct.

From Encyclopaedia Britannica, 11th Edition, Volume 12, Slice 7 "Gyantse" to "Hallel" by Various