Flowers are modified Leaves. This is not readily apparent in most cases. However, there are cases in which floral organs display a gradient of leaf traits starting with the Sepals which are most leaf-like to Carpels which are highly specialized and do not resemble leaves.

Receptacle = Place on stem where floral organs originate & attach

Sepals = Lowest order of floral organs, first to develop, can be green & leaf-like, Collectively = Calyx

Petals = Inserted on the Receptacle just above the Sepals, usually brightly colored, Collectively = Corolla

Perianth = Collective term for Sepals + Petals

Stamen = Inserted above Petals, consists of Anther & Filament, Collectively = Androecium

Anther - Part of Stamen that Produces Pollen

Filament - Stalk that bears the Anther

Carpel = Inserted above Stamens, uppermost floral organ, Consists of Stigma, Style & Ovary, Collectively = Gynoecium

Stigma - Tip of the carpel, Receptive to Pollen

Ovary - Base of the carpel, contains Ovules

Style - Connects the Stigma to the Ovary

Apocarpous   - Flower with Free Carpels

Hypogenous   - "Superior Ovary" - Other floral organs attached below the gynoecium on the receptacle.

Coalescence or Fusion - Fusion or union of floral organs from the same whorl or type -  Designated by Sym or Syn

Syncarpous   - Fused Carpels

Synandrous - Fused Stamens

Sympetalous - Fused Petals - Synsepalous - Fused Sepals

Adnation - Fusion between floral parts of a different kind or whorl

Fusion of Calyx & Corolla - Fusion of Androecium & Corolla

Datura Flower with Adnation between the Corolla and Androecium

Hypanthium = Fusion of Calyx, Corolla & Filaments of Androecium -> Perigynous Flower

Perigynous Flower in Rosaceae

Fusion of Hypanthium to Ovary -> Epigynous Flower with Inferior Ovary

Apple (Purus) Flower with Petals removed

Complete   - Has all four floral Organs

Incomplete   - One or more floral organs missing

Perfect - Flower with Androecium & Gynoecium

Imperfect   - Missing Androecium or Gynoecium

Carpellate Flower - Imperfect that has Carpels only

Staminate Flower - Imperfect that has Stamens only

Monoecious (One House) - One plant has BOTH Carpellate & Staminate Flowers

Dioecious (Two Houses)- One plant has only staminate flowers & another plant has only Carpellate Flowers

Hypogenous   - "Superior Ovary" - Other floral organs attached below the gynoecium on the receptacle.

Perigynous   - Sepals, Petals & Stamens arise from a tubular extension of the receptacle called the Hypanthium which surrounds the Ovary but is NOT fused to the Ovary Wall.

Epigynous   - "Inferior Ovary" - Stamens, Petals & Sepals appear to grow from the top of the Ovary

Actinomorphic   - Face of Flower has Radial Symmetry

Zygomorphic - Face of Flower has Bilateral Symmetry