Double flower
A flower with many more petals than the wild form, often with stamens turned into petals.
Also: double, flore pleno
A single flower has the normal number of petals for its kind. A double has extra ones, packed in layers. In many doubles the stamens, and sometimes the pistil, have changed into petals, so the flower gives little pollen or nectar and may set no seed. People have prized doubles for a very long time: most garden roses, peonies, camellias and carnations are double. In older plant names the Latin words flore pleno, meaning full flower, mark a double form.