Meristematic cells that give rise to the organs of flowers. The primordia are arranged into four concentric whorls as shown on page 162. The leaf-like sepals form whorl number 1 at the periphery. The showy petals form whorl 2, inside the first. The stamens, the male reproductive organs, form whorl 3 (inside whorl 2), and the carpels, the female reproductive organs, form central whorl 4. See Classification, Plantae, Angiospermae; Arabidopsis thaliana, floral organ identity mutations, meristems.
Subjects: Genetics and Genomics.