Flowers are the site of sexual reproduction in In contrast...

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Transcript of Flowers are the site of sexual reproduction in In contrast...

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