Pinophyta--the conifers, or cone bearers--have ovules and seeds that are unprotected by ovary or fruit tissue. The conifers are therefore classified as gymnosperms or "naked-seeded". One tree produces two distinct cones that are either pollen- or ovule-producing, but never both. Beneath each scale on the cones lie either a pollen-producing structure, or an ovule, making each cone either a male staminate or female ovulate.
The Reproduction Process
In the spring, the very small, male, staminate cones produce pollen. The wind disperses the pollen to the larger, female, ovulate cones where fertilisation occurs. The pollen and megaspore (male and female cells) are both haploid cells. Once united, the two haploids become a diploid cell and grow into a zygote or baby conifer. One tree may fertilise its own ovulate cones or the pollen may drift to fertilise the female cones on another tree nearby.
Seed Development and Dispersal
The pollen-producing cones fall from the tree while the cones containing the fertilised ovules grow larger and become seeds. At maturity, the scales of the ovulate cones open and the seeds drop to the ground or are dispersed by wind, water, people, or wildlife. In some cases, seeds are carried by the wind for considerable distances before they find a fertile place to sprout. Fortunately, conifer seeds are extremely hardy.
Conifer Reproduction Advantages
Plants, such as mosses and ferns, that produce spores instead of seeds, must grow near water in order to survive. A spore is a tiny bag which contains a piece of the parent plant. If a spore does not land on fertile, moist, ground right away, the delicate cells will die. Conifers produce hard-coated seeds that can live for a long time until they find a good place to grow. Some conifer seeds can survive for years before sprouting.
The Self-Reliant Conifers
The most advanced plants produce flowers rather than cones. These plants depend upon their flowers and a great deal of outside help for successful reproduction. Insects and animals are called upon to move pollen from flower to flower and, in many cases, from plant to plant so that fertilisation may occur. The seeds of these flowering plants must be protected by ovary or fruit tissue in order to survive and mature. The conifers can pollinate themselves and thereby better ensure species survival.