Floral Terminology (Illustrated)
Table of Contents
FLORAL TERMINOLOGY
Receptacle
The more or less enlarged or elongated stem axis on which the floral parts are attached.
Peduncle
The stalk of a solitary, terminal flower (or the stalk of an inflorescence).
Sepals (calyx)
First series; the outermost whorl or spiral of a typical flower (asexual/sterile).
Petals (corolla)
Second series; the second whorl or spiral of a typical flower (asexual/sterile); petals alternate with sepals.
Stamen(s) (androecium)
Third series; the third whorl or spiral; the male reproductive unit; stamens alternate with petals and are opposite the sepals.
Filament
Stalk of a stamen.
Anther
The pollen-producing portion of a stamen (meiosis occurs within the pollen sacs).
Pollen
The male gametophytes.
Connective
The sterile tissue connecting the two locules of an anther.
Carpel(s) (gynoecium)
Fourth series; the terminal or centermost component; the female reproductive unit (the site of pollination and fertilization); 1 to many separate or fused carpels comprise a gynoecium.
Synoecious
A sexual condition in which the flowers on a plant are all perfect
Monoecious
Both staminate and carpellate flowers occur on the same plant
Dioecious
Staminate and carpellate flowers occur on different plants
Stigma
The pollen-receptive portion of the gynoecium.
Style
The elongated portion between stigma and ovary specialized for pollen tube growth.
Ovary
The basal portion that surrounds and protects the ovules (meiosis occurs within the ovule).
Corona
An extra series of floral parts. Coronal structures are often showy and diverse and are formed from outgrowths of the perianth parts, stamens, or receptacle.
Complete
All four floral series present (Ca, Co, A & G).
Incomplete
One or more floral series absent
Perfect
Flower with both functional androecium and gynoecium
Imperfect
Flower lacking either a functional androecium or a functional gynoecium:
Staminate
A male flower; one that has a functional androecium but lacks a functional gynoecium
Carpellate
A female flower; one that has a functional gynoecium but lacks a functional androecium
Synoecious
A sexual condition in which the flowers on a plant are all perfect
Monoecious
Both staminate and carpellate flowers occur on the same plant
Dioecious
Staminate and carpellate flowers occur on different plants
Distinct
Similar parts (of same embryonic origin) not fused
Connate
Similar parts fused
Adnate
Parts of different origin that are fused
Free
Unlike parts that are not fused
Biseriate
In two whorls or series (e.g., calyx and corolla)
Uniseriate
In one whorl or series (e.g., calyx only)
Apetalous
Lacking petals
Sympetalous
Having the petals united (connate) at least at the base
Floral tube (cylindrical base), throat (gradually opening), and lobes
3-merous, 4-merous, etc.
Indicates the number of parts in a specific floral series (e.g., a 4-merous flower might have four sepals, four petals, eight stamens, and four carpels)
Androecium
Staminodes
Sterile stamens (they do not produce pollen); variable in form and size, maybe petaloid or secrete nectar
Epipetalous
Stamens adnate to corolla
Alternating with petals or corolla lobes
Opposite petals or corolla lobes
Hypanthium (floral cup)
A structure derived by the adnation of the perianth bases and stamens. It is variously shaped.
Gynoecium
Carpels 1 per flower (monocarpous gynoecium)
Carpels more than 1 per flower:
- Carpels distinct (apocarpous gynoecium)
- Carpels connate (syncarpous gynoecium)
Pistil
Equivalent to gynoecium; formed from one or more carpels
Simple pistil
A gynoecium with one carpel
Compound pistil
A gynoecium with two to many separate or fused carpels (it combines both apocarpous and syncarpous gynoecia)
INSERTION
The method of attachment of one structure to another
SUPERIOR OVARY
Ovary situated ABOVE the point of attachment of the perianth and androecium and wholly free from them (stamens may be adnate to Corolla)
HYPOGYNOUS FLOWER
A flower with perianth and androecium arising from below the ovary (gynoecium).
PERIGYNOUS FLOWER
(If hypanthium not adnate to the ovary) – a flower with perianth and androecium arising from a floral cup that is NOT adnate to the ovary. Remember – the ovary is still superior!
INFERIOR OVARY
An ovary is BELOW the point of attachment of the outer flower parts (perianth and androecium). In other words, the outer floral whorls are adnate to the ovary. A hypanthium (floral cup) may or may not be present.
EPIGYNOUS FLOWER
(if hypanthium adnate to the ovary) – A flower with perianth and androecium apparently arising upon the ovary (rather than the receptacle).
Carpel
- The basic unit of the gynoecium
- The foliar, ovule-bearing unit of a flower that forms either all (monocarpous or apocarpous) or part (syncarpous) of the gynoecium.
- Leaflike megasporophyll with infolded or inrolled connate margins bearing one or more ovules on the inside.
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