floral Genome Project Education Site  


Flower basics

The flower is the reproductive structure for flowering plants (angiosperms). Flowers are extremely diverse in size, shape, color, smell, and features, making them excellent tools for distinguishing species. 


There are four distinguished floral organs, arranged in several whorls, or rings.  Any number of these parts may be fused, modified, or absent in a flower.  Begining from the base of the flower, the receptacle, the first organ is the calyx, consisting of a ring of sepals. The next level up is the corolla, composed of petals.  If the sepals and petals are indistinguishable (all petal-like) they are collectively called tepals. The next organ is typically the androecium, the male reproductive portion, composed of stamens.  Fertile stamens contain pollen, which hold sperm nuclei. The central most or highest organ is the gynoecium, the female reproductive portion, comprised of one or more carpels. Carpels hold the egg cells. If a flower is fertilized, ovaries protect the developing seeds and the flower matures into a fruit.

For further information visit:
Education site, James Madison University, VA:

Education site, Andromeda Botanic Gardens, Barbados:

Flower Structure. Plant Physiology Information Website, by Ross E. Koning:

Author: Heather Fara, University of Florida. Send comments or corrections

University of FloridaPenn StateCornell UniversitySupported by NSF