Nutrient-rich, tissue associated with seed formation in angiosperm plants.
Endosperm is one of the two products of double fertilization, the other being the zygote.
The endosperm takes the place, in many angiosperms, of the nutrient support of the developing embryo by the gametophyte, that is, the as seen with gymnosperms. The endosperm nonetheless is a mitotitc product of the megagametophyte, so this change to use instead of endosperm is one of degree rather than something more radical.
Note the endosperm is a key basis of such as generated from as well as of the that supports production.
The of , like , is predominantly endosperm.