If we look at a section of a developing anther we find four sporangia with an outer wall of diploid cells enclosing a layer of nutritive tissue, the tapetum, and inside this the microsporocytes. The microsporocytes undergo meoisis to produce tetrads of four spores - pollen grains. The nucleus of the immature pollen grain divides mitotically to form a tube cell and a generative cell - the latter will divide at some stage to produce two sperm cells. There is an opening in the nucellus called the micropyle. The archegonium which has been a constant feature of the female gametophyte up to this point is not formed.
Pollination occurs when a pollen grain lands on the stigma.
The pollen grain germinates and sends a tube down the style and into the micropyle. The sperm nuclei move down the pollen tube and enter the embryo sac by way of a synergid, which degenerates. The triploid cell divides to produce the endosperm. This provides a food reserve and is well developed in many monocots. The lobes of the heart form the fins of the torpedo which grow into the cotyledons.