The nutritive tissue in the seeds of higher plants is known as endosperm. The endosperm is a tissue that is formed during the process of double fertilization in angiosperms. It is typically triploid, meaning it contains three sets of chromosomes. The endosperm provides nourishment to the developing embryo, supplying it with essential nutrients such as proteins, sugars, and oils. It acts as a food reserve for the growing plant until it is able to perform photosynthesis on its own. The other options provided in the question refer to different parts of the seed. The hypocotyl is the embryonic stem, the embryo is the fertilized ovule from which the plant develops, and the nucellus is the central part of the ovule.