Parts of a Flower
Pedicel -the stalk of an individual flower
Sepal --one member of the outermost whorl of
a flower. Collectively, the sepals make up the
calyx. The sepals may be free or fused.
Petal --one member of the second whorl of a flower.
Collectively, the petals make up the corolla. The
petals may be free (the flower then termed
polypetalous) or fused into one piece (the flower then
Complete flower – when calyx, corolla,
androecium and gynoecium are present
Incomplete Flower – when one of the four
Unisexual flower – androecium
(staminate) or gynoecium (pistillate) any
one of them are present in the flower.
Bisexual flower – both male and female
are present in a flower.
Monoecious plant – when both male and
female flowers are present on the same
Dioecious plant – When male and female
flowers are present on separate plant.
An assessment of the
presence and number of
mirror-image planes of
Actinomorphic/ Radial / Regular
- When flower is divided by any
vertical plane into two equal halves
Zygomorphic / Bilateral - when flower is
divided into two equal halves only by one
Assymetrical / Irregular
When flower cannot be divided into
equal halves from any plane.
member of the whorl
of male sex parts.
The part of the
flower that produces
pollen. This consists
of two parts.
The anther or top of
the stamen actually
produces the pollen.
the anther is held
aloft by a
filament which is like
a stem of the
Each stamen consists of a filament and
anther, where pollen is produced.
Collectively, the stamens make up the
Types of Stamens
- refers to four long
and two short stamens
in one flower
2. Monadelphousrefers to
by the filaments
into one column
to stamens united
by the filaments into two groups--often 1
in one group and 9 in another
- one member of the whorl of female sex parts.
- Collectively, the carpels make up the
- Each carpel consists of an ovary connected to
a stigma by a style.
- The stigma is receptive to pollen. Within the
ovary, on the placentae (sing., placenta) are one
or more ovules, which will mature into seeds.
- The open spaces inside the ovary are called
locules or cells. The dividing walls are called
Carpel = inserted above the
= uppermost floral
= consist of Stigma,
Style and Pistil
Stigma - Tip of the carpel, receptive to
Ovary - Base of the carpel, contains Ovules
Style - Connects the Stigma to the Ovary
Types of Carpels
- The flower is said
to have many simple
- A gynoecium of
many separate carpels
In the very center of the flower is a single
carpel. A carpel is the basic unit of a
This flower only has one carpel, and flowers
like this are said to have a monocarpous
with only one
- The flower
has a simple
A hypanthium (= floral cup) is a structure derived by the
adnation of the perianth bases and stamens. It can be
variously shaped. This is a line drawing corresponding to a
longitudinal section of a Prunus (cherry) flower.
hypogynous if the
ovary is situated
above the calyx and
there is no floral cup
around it. The ovary
-The flower is
perigynous if the
ovary is situated
within (and free
from) a floral
The ovary is
When the perianth and the stamens arise from a
hypanthium that is NOT adnate to a superior
ovary, the insertion is said to be perigynous, as
in this longitudinal section of a flower of black
cherry Prunus serotina.
--The flower is
epigynous if the ovary
is situated below the
calyx. The ovary is
inferior. (In the
graphic example, the
calyx is pink and the
flower hangs upside
Bracts = specialized leaves present in axis of flower.
Involucre = the whorl of bract surrounding
Different types of inflorescences
- a spike-like
inflorescence (i.e. the
flowers do not have a
pedicel and the main axis
is elongated and
unbranched) which has
only male or female
flowers. They occur in
many woody trees such
as the hazelnut and the
A willow catkin (Salix sp)
Left: Male (staminate) catkin from the white mulberry (Morus
alba), a fruitless variety commonly planted as a shade tree in
southern California. Right: An individual male flower containing
four stamens, each with an anther and a filament. At the base of
each filament is a fleshy green sepal.
Female flowers consist of single pistil tightly enveloped by four
inconspicuous sepals. Each carpel or pistil (also referred as a
gynoecium) consists of a forked stigma, a short style and a
spherical ovary. Each ovary (carpel) becomes a drupelet and the
ripened cluster of drupelets (syncarp) is called a multiple fruit.
In the aggregate fruit of a blackberry, all the drupelets of the
cluster (syncarp) come from a single flower
- is the characteristic inflorescence
of the remarkable arum family
- It consists of a thickened, fleshy
axis (spike) bearing clusters of
sessile, apetalous, unisexual flowers.
The small unisexual flowers are packed together
along the lower region of an erect, phallus-like
central spike, typically with male flowers
above the female.
- The upper region of the spadix is usually
devoid of flowers.
- Male (staminate) flowers consist of
numerous stamens packed together,
- while female (pistillate) flowers consist of
numerous individual pistils.
- Individual flowers are reduced to a
single stamen or pistil (gynoecium).
- The spadix emerges from a vaseshaped or funnel-like modified leaf or
spathe which is often brightly colored.
- The spadix of some arums emits a
putrid odor that attracts carrion flies for
The bizarre Malaysian Amorphophallus paeoniifolius.
An enlarged, inflated, flower-bearing spadix protrudes
from the vase-shaped spathe. Clusters of yellow male
flowers (stamens) can be seen above the whitish stigmas
of female flowers (pistils).
main axis and all
the pedicels of the
flowers are more
or less the same
Sweet pea (Lathyrus odoratus)
Chinese hat (Holmskioldia sp.)
- The peduncle of this type of inflorescence
bears all of the pedicels at its apex.
Lantana (Lantana sp)
- The peduncle
bears a number of
primary pedicels at
its apex. These do
no bear flowers
but a number of
at their apices
which in turn bear
Frangipani (Plumeria rubra)
has a long,
axis which bears
have no pedicels
or very short
Silver oak (Grevillea robusta)
tree (Aloe dichotma)
Red hot poker
- which do not have pedicels
- are grouped together on the top of a peduncle
which may be flattened or rounded.
- Daisies (Asteraceae) are a good example
- outer flowers may have one very large petal
- In other families the whole inflorescence may be
surrounded by bracts e.g. the Proteas.
- This gives the impression that the whole structure
is a single flower but it may in fact be hundreds of
flowers grouped together.
King protea (Protea
- The main axis of this
inflorescence type is
elongated and unbranched
as in a raceme, but the
pedicels of the flowers are
of unequal length so that
the entire structure appears
include hawthorn, the
apple and dogwood.
Hydrangea corymb (group
of flowers displayed as a