As was true in the gymnosperms, the "main plants" in angiosperms are sporophytes, while the gametophytes are confined to the flowers, usually male and female together. Male gametophytes are called stamens, female gametophytes are pistils. The pollen from the stamen has to reach the pistil and make a pollen tube to the base of the flower, the ovary, and the ovules, where the egg cells are. Once the egg cells are fertilized, the embryos are sealed up with food in a seed and the ovary is converted into a fruit.
The seeds often wait for some environmental cue, such as warmth, moisture, or light periods shifts, before germinating, sprouting. A type of growth hormone known as auxins, which settled to the bottom of the sprouting root and stem as they emerge, have different effects on those parts: auxin-soaked root cells grow more slowly, making the top of the root grow faster and curve the root downward; auxin-soaked stem cells grow faster, curving the stem up.
In a mature plant, auxins migrate away from the sunlit side of the plant - if the light is coming in from the side, the migration causes the stem to curve toward the light as it grows and better orient the leaves to catch light. Plants produce many different types of hormones that can affect reproduction, overall growth, defenses, fruit ripening, and other features.
Production of new cells in plants happens in a type of tissue called the meristem. Meristems can be, and usually are, at the growing tips of the plants, where they are called apical meristems. Most plants add new cells from the tips out, not evenly all over and not from the bottom up - in the other parts of the plant, the cells grow but do not divide. Leaves, branching stems or roots, and flowers all are produced by apical meristems. Some growth may also occur along the sides of the plants, such as is found in the rings of trees - these are called lateral meristems. These make tree ring patterns in ecosystems with growing seasons, where growth produces big, "light" cells, alternating with seasons of less growth (cold winters or dry periods), which produce smaller, "darker" cells - each light/dark zone is a ring, and the wider, lighter the ring, the better that growth season, leaving a record of year-to-year climate.