, the central structure around which are arranged the stamens, the petals, and the sepals. The pistil is usually called the female reproductive organ of a flowering plant, although the actual reproductive structures are microscopic.The pistil has a bulbous base (the ovary) containing the ovules, which develop into seeds after fertilization of egg cell(s) in the ovule.A pistil is composed of one or more highly modified leaves (carpels), each containing one or more ovules. the central structure around which are arranged the stamens, the petals, and the sepals. The pistil is usually called the female reproductive organ of a flowering plant, although the actual reproductive structures are microscopic.