Most people recognize dill as a familiar and flavorful addition to a variety of dishes. The seeds and foliage provide this flavor. Less well known are the umbrella-shaped constellations of yellow flowers that top their stalks, with a shape reminiscent of Queen Anne's Lace. The flower's stem, or peduncle, leads to sepals, small leaves underneath the flower, collectively called the calyx.
The pistillate, or female flowers, of the dill plant occur along with hermaphrodite blooms anywhere outside the center of the umbrella of flowers. Ovaries, ovules, petals, styles and stigmata comprise the pistil, the primary structure of the female flowers. The stigma, style and ovary make up a larger structure within the pistil called the carpel. The dill flower typically has two carpels and, therefore, two ovaries. The two ovaries at the base of the pistil contain the ovules, and--with pollen received by the stigma--house the seeds that develop as a result of pollination. The stigma features a sticky film, nectar, to which the pollen from the male flower adheres. Underneath the stigma lies the style, a small tube that transports the grains of pollen received by the stigma down into the flower's ovary, where it fertilizes ovules that lie within.
The staminate, or male, flowers responsible for producing pollen occur primarily in the center of the flower umbrella. The structure that creates pollen for fertilization, the anther, appears at the top of a stalk in the flower. Two theces make up the anther, and each theca contains two pollen sacs that produce the flower's pollen grains. The two most common ways that pollen grains from a male or hermaphrodite flower find their way to female or other hermaphrodite flowers are via wind or insects. Wind can transport lightweight pollen grains to the stigmata of neighboring flowers. Bees, the most common of the pollinating insects, require both nectar and pollen to make wax. As they fly from flower to flower, pollen grains adhere to their bodies and stick to the stigmata where they are then able to fertilize the ovules of a female or hermaphroditic flower.
Hermaphrodite flowers of the dill plant may appear alongside female flowers, anywhere outside the center of the umbrella. They feature a stigma and anther, so that they may pollinate themselves and produce seeds within one flower. Quite common among dill flowers, hermaphrodite blooms help create a better chance of successful seed creation and distribution. Some scientists and gardeners refer to hermaphrodite flowers as perfect flowers because of their unique ability to self pollinate and of course to pollinate one another. The presence of male, female and hermaphrodite flowers on a single dill plant makes it a trioecious species, a term that refers to any plant species that bears all three types of flower.