Albumen

Albumen, a term used in botany as a convenient name for the reserve nutriment in a seed external to the embryo, whether it be within the embryo-sac (endosperm) or outside it (perisperm). If no such store exists in the ripe seed it is exalbuminous; but, if present, as in almost all monocotyledons, it may vary considerably in amount or in texture. In the vegetable ivory (Phytelephas) it is very hard; in the coffee it is horny; in the poppy, it is oily; and in corn, it is mealy. Though it may contain aleurone (q.v.), its composition is largely non-nitrogenous, and it is in no respect identical with true albumin, deriving its name simply from the analogy of its position and use to the seedling with that of the "white" of an egg to the chick.