Many plants can reproduce both sexually and by vegetative propagation. Sexual reproduction in plants happens with the complex cycle we call alternation of generations. It may produce one or the other or both, depending on the plant species. Fertilization occurs when the sperm and egg cell unite and the egg develops into the second phase of the plant's life cycle where the plant is called a sporophyte or spore-bearing plant. This spore-bearing part of the plants life is typically what people see and recognize as a plant.
Sporophytes produce tiny structures called spores through a process of cell division called meiosis.
The spores form in capsules called sporangia. Gametophytes develop from the spores, and the life cycle begins again. With seed plants, which include flowering and cone-bearing plants, alternation of generations involves a series of complicated steps. With these plants, only the sporophyte generation can be seen with the unaided eye. Spores are produced in both male and female reproductive organs.