Northern Ontario Plant Database

General Floral Terminology

• flower - the modified reproductive shoot of an angiosperm. When all parts are present, consisting of a whorl of sepals, petals, stamens, and pistil.
• solitary flower - a single flower borne on a peduncle.
• inflorescence - a cluster of flowers.
• bract - a modified leaf subtending a flower or located in an inflorescence.
• merous - the suffix used to describe the number of floral parts in each whorl. A plant with floral parts in multiples of 3 (3 petals, 3 sepals, 6 stamens, and a single 3-carpelled pistil) is considered to be 3-merous. Most higher angiosperms are either 3-, 4-, or 5-merous.

sterile floral structures

• petal - the inner sterile whorl of a flower, often colourful to attract pollinators.
• corolla - a collective term for all the petals.
• sepal -the outer sterile whorl of a flower, usually green.
• calyx - a collective term for all the sepals.
• tepals - petals and sepals that are alike in colour and shape.
• perianth - a collective term for all the petals and sepals.
• hypanthium - a floral structure formed by the fusion of floral parts around a pistil
• receptacle (or torus) - the basal portion of a flower to which all floral parts are attached.

male floral structures

• stamen - the male reproductive organ of a flower.
• anther - the fertile portion of a stamen, the part in which pollen is produced, usually consisting of 4 microsporangia.
• filament - the sterile portion of a stamen, supports the anther.
• androecium - a collective term describing all the stamens in a flower.

female floral structures

• carpel - the female reproductive organ of a flower; one unit of a compound pistil.
• pistil - the female reproductive organ of a flower, composed of 1 to several carpels.
• stigma - the pollen receptive structure at the top of a pistil.
• style - the stalk between the stigma and the ovary.
• ovary - the fertile part of the pistil, containing the ovules and developing into the fruit.
• locule - the chamber in a carpel, within which the ovules are located.
• ovule - the nucellus (megasporangium) and integuments, contains the egg nucleus.
• gynoecium - a collective term describing all the pistils in a flower.