What is mean by endosperm​

Ancestral flowering PLANTS have seeds with small embryos and abundant endosperm, and the evolutionary development of flowering plants tends to show a trend towards plants with mature seeds with little or no endosperm. In more derived flowering plants the embryo occupies most of the seed and the endosperm is non developed or consumed before the seed matures.Explanation:The endosperm is a tissue produced inside the seeds of most of the flowering plants following fertilization. It is triploid in most species.It surrounds the embryo and provides nutrition in the form of starch, though it can also contain oils and protein. This can make endosperm a source of nutrition in animal diet. For example, wheat endosperm is GROUND into flour for bread (the rest of the grain is included as well in whole wheat flour), while barley endosperm is the main source of sugars for beer PRODUCTION. Other examples of endosperm that forms the BULK of the edible portion are coconut "meat" and coconut "water", and corn. Some plants, such as orchids, LACK endosperm in their seeds.