The Dianthus genus is home to more than 300 flowering species, chiefly among them, the carnation (D. caryophyllus), the sweet william (D. barbatus) and the many blossoms known as pinks. The genus has a long history dating back to the ancient Greeks and Romans; in fact, the name "Dianthus" comes from the Greek words "dios" (divine) and "anthos" (flower). These sun-loving plants will brighten up your garden through the spring and summer and, in some cases, right up until the first frost.
Stems and Leaves
The stems of flower species in the Dianthus genus grow straight and tall, with most varieties reaching a height between 10 and 20 inches. The stem of the sweet william may reach up to three-fourths of a meter. Elliptic or oblong leaves grow in opposed pairs from knobby joints in the stem. The stem sometimes branches at these joints.
Sepals and Calyx
Sepals are the small petal-like leaves directly underneath the flower. The complete whorl of sepals is known as the calyx. In the Dianthus genus, the calyx tends to form a fused tube-like sheath. The calyx of the sweet william may be up to 1 cm long.
Petals and Corolla
Dianthus flowers bear petals in shades of white, red, pink, lavender or yellow. The petals' outer edge is not smooth but rather notched as though cut by pinking shears. It is this uneven texture of the petals' edges, and not their color, that gave some Dianthus species the name "pinks." The group of petals that make up the blossom is known as the flower's corolla. The number of petals in the corolla is not consistent across the genus. The corolla of some species, including D. barbatus and D. armeria, consist of five petals; the carnation may have up to 40.
The androecium, or male reproductive organ, is a single filament, called a stamen, topped by the pollen-producing anther. D. barbatus and D. armeria have 10 stamens. Carnations vary in number of stamens.
The gynoecium, or female reproductive organ, takes the form of a capsule in the base of the flower, known as a carpel. The group of carpels together is known as the pistil. Each carpel contains an ovary. The ovary produces ovules, or female reproductive cells, which will develop into seeds. Pollen reaches the ovules via a tube, known as a style, after being collected on the protruding stigma.
Because Dianthus flowers have both gynoecia and androecia, they are considered "perfect flowers." They are also considered "complete" for having all four parts needed for that categorization: stamens, pistil, petals and sepals.