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The region at the base of the nucellus of an ovule; gives rise to the integuments.
(cell and molecular biology)
One of the paired, spiral, albuminous bands in a bird's egg that attach the yolk to the shell lining membrane at the ends of the egg.



the basal part of the ovule where the seed stalk attaches the ovule to the placenta.

References in periodicals archive ?
For example, Halloin (1975) observed that certain fungi entered cotton seeds predominantly via the chalaza.
The basal part of the tegmen undergoes intercalary growth and vascularization that comes from the chalaza (Figure 4A), characterizing the formation of an endopachychalaza.
The seed body bears a conspicuous long oval/oboval germination valve similar to that found in extinct Decodon and Microdiptera seeds and a similarly positioned raphe, chalaza, and hilum.
Confusion between chalaza and nucellus originates from the general practise of referring to the (proximal) part of the nucellus nearest the chalaza as the "chalazal region of the nucellus," or "chalazal nucellus.
Seed anatomy of Artabotrys odoratissimus with a discussion on chalaza, integumentary bundles and ruminate endosperm.