Post on 21-Jun-2020
Flower Parts include:
Survey of Flower Terminology
Flowers are the site of sexual reproduction in
angiosperms.
In contrast to the vegetative portions of the plant, flowers
are very little influenced by environmental changes
The parts of the flower are arranged in successive
whorls above the receptacle.
1)Receptacle where the flower is attached to the flower stem
2)Perianth – the showy petals and (usually) green sepals
3)The androecium, composed of stamens
4)The gynoecium, composed of pistil or carpel.
The first whorl is composed of sepals.
The sepals are collectively referred to as the calyx.
The second whorl is made up of petals.
The petals are collectively referred to as the corolla.
The Corolla
Because the corolla is often the largest and
most conspicuous whorl in the flower, it usually
has the most to do with determining the overall
appearance of the flower.
The shape of the corolla depends on the
number, relative size, placement, and shape
of the petals.
Survey of Flower Terminology
The petals and sepals together are called the perianth.
In many flowers, the petals are brightly colored in order to
attract pollinating insects or other animals.
The sepals are often green, but may also be brightly
colored and look much like petals.
Sepals generally function as protection for the rest
of the flower.
The next whorl of the flower is the androecium,
comprised of stamens.
The stamens have 2 parts, the slender filament and the
anther, which rests on top of the filament.
The final whorl is the gynoecium, the female part of the flower.
The gynoecium comprises one or more carpels.
The androecium consists of the stamens of a
flower,usually arranged in a spiraled or
whorled pattern.
The pistil can either be a single carpel or multiple carpels
fused together.
At the base of the pistil is the ovary, where the egg cells
are formed and fertilization occurs.
An elongate style elevates the stigma above the ovary.
The stigma is where pollen lands, which is the first step
toward fertilization of the egg.
The Gynoecium: structures of the carpel.
The simplest gynoecium is a pistil
comprised of a single folded carpel, also
called a simple pistil.
More often, there are several separate carpels or fused
carpels. A group of fused carpels is called a compound
pistil.
Flowers Vary in their Architecture
A flower with all four parts is a complete flower.
If it lacks one or more parts, it is an incomplete flower.
If a flower has both androecium and gynoecium (male
and female) it is called a perfect flower.
If only one sex is present, it is an imperfect flower.
Symmetry is also used to characterize flowers
Regular symmetry is when all the flower parts
Sedum
Irregular symmetry is when the flower parts are not equal.
Pisum
Flower parts may be free or united (fused).
Sedum In Sedum, the petals, sepals, stamens, and pistils are
completely separate and free.
In Narcissus, the petals are fused over part of their length
to form a tube.
In some plants, the ovaries are clearly situated above the point of attachment of the other flower parts.
In other plants, the ovaries appear to be placed below the point of attachment of the other flower parts.
Superior ovary in Tulipa. Inferior ovary in Narcissus.
Narcissus
Ovary position also varies.
A cluster of flowers is called an inflorescence.
Monocot Dicot
-Understand floral structure
-Know terms-receptacle, perianth, androecium, gynoecium, sepal, calyx, petal, corolla, stamen, anther,
filament, carpel, pistil, stigma, style, ovary
-Know different flower shapes-funnelform, cruciform, salverform, trumpet-shaped, campanulate, disk and ray floret
(head), tubular, papilionaceous, urceolate,
-Know different types of inflorescences-solitary, raceme, cyme, spike, head, spathe and spadix, umbel, compound
umbel, catkin
-Know terms relating to floral structure-imperfect vs. perfect, complete vs. incomplete, regular vs. irregular
inferior vs. superior ovary, fused vs. free
-Know differences between monocot and dicot flowers