Final answer:
Female cones are placed on the upper branches to improve pollination efficiency by utilizing wind patterns to carry pollen from male cones. The ovules within these cones are fertilized by wind-blown pollen, which leads to seed development encompassing three generations of tissues.
Step-by-step explanation:
Female cones, also known as ovulate cones, are typically located on the upper branches of conifers for effective pollination. They are fertilized by pollen from male cones, which are carried by the wind. This positioning takes advantage of the wind patterns that naturally move pollen upwards through the canopy of a tree.
The scales of female cones are initially open to allow for the entry of pollen grains, which are then trapped by a sticky substance called a pollination drop. After rehydrating in this drop, the pollen can fertilize the ovule, which eventually develops into a seed. The seed contains tissues from multiple generations: the parent plant tissue forming the seed coat, the female gametophyte providing nutrients, and the developing embryo.