Pollen cones and ovulate cones are distinct structures found in gymnosperms, primarily conifers, with noticeable differences in their appearance.
Pollen cones, also known as male cones, tend to be smaller and cylindrical in shape. They are usually found in clusters on the lower branches of the tree and have a woody or papery texture. Their main function is to produce pollen grains, which contain the male gametes.
In contrast, ovulate cones, or female cones, are typically larger and more robust. They often have a more complex, woody structure with spirally arranged scales. The ovulate cones are usually positioned higher up on the tree, allowing for better exposure to wind for pollen transfer. The scales protect the ovules, where the female gametes are housed.
Within both types of cones, an important process occurs in the sporangia. In pollen cones, the sporangia are located on the surface of the scales, where they produce pollen through meiosis, a process that results in haploid spores. This pollen is then dispersed by the wind to fertilize ovules in ovulate cones. In ovulate cones, the sporangia also undergo meiosis, but in this case, they produce ovules that develop into seeds once fertilization occurs. Thus, sporangia play a crucial role in the reproductive lifecycle of these plants.