The Flower
A flower can be divided as below based on the reproductive structure it has:
▪ Bisexual Flower – A flower that contains both male and female reproductive
structures is
called a bisexual flower. Bisexual flowers are also called hermaphrodites. They are
perfect
flowers.
▪ Unisexual flower – A flower that has only one reproductive structure, either male
or
female, is called a unisexual flower.
▪ Staminate flower: A unisexual flower, which contains the only androecium is
called a
male or Staminate flower.
▪ Pistillate flower: A unisexual flower, which contains the only gynoecium is called
a
female or Pistillate flower.
▪ Neuter flower: A flower in which both male and female reproductive organs are
absent is
called a neuter flower.
Sexuality in plants:
In most plants, the flowers are bisexual. They contain both male and female
reproductive parts.
In some plants, the male and female flowers are separate. These plants are of two
types—
monoecious and dioecious.
1. Monoecious plant: If the male and female flowers grow on the same plant, then the
plant
is said to be a monoecious plant. Examples: Pumpkin, Maize, Cucumber
2. Dioecious plant: If the male and female flowers grow on separate plants, then the
plant is
said to be a dioecious plant. Examples: Palm, Papaya.
Complete and Incomplete Flowers:
When all the four whorls of the flower are present, it is called a complete flower. All
bisexual
flowers are generally complete flowers.
Example: Hibiscus
Some flowers have only the male parts (Staminate) or only the female parts
(Pistillate). These are
called unisexual or incomplete flowers.
Example: papaya
Unisexual flowers may occur on the same plant at different places. These are called
monoecious
plants
Example: maize, cucumber.
If male and female flowers occur on different plants, they are called dioecious plants
, Example: palms.
Essential/ Reproductive Whorls:
The essential whorls of a flower are the whorls that are directly associated with the
process of
reproduction. A flower cannot function as a reproductive organ in the absence of
essential whorls.
Examples: Stamen and carpel.
Non- Essential/ Non-Reproductive Whorls:
The non-essential whorls of a flower are the whorls that are not directly associated
with the process
of reproduction. They are the helping parts, which either protect the reproductive parts
of the
flower or make them attractive for pollination. A plant is able to reproduce in the
absence of nonessential
whorls.
Examples: Calyx and corolla
Perianth:
In plants, such as wheat and grasses, the petals and sepals are undifferentiated and
together
compose the perianth.
Petaloid perianth: In some plants, the sepals are not green but appear brightly
coloured as the
petals. These sepals are called petaloid sepals, and the perianth is called a petaloid
perianth.
Example: Orchid
Sepaloid perianth: In some plants, the petals appear green in colour and are called
sepaloid
petals. The perianth is called a sepaloid perianth.
Examples: Viscum, Mistletoe.
Nectaries:
Nectar is a sugary liquid produced by plants. The nectar in flowers is secreted by a
group of cells,
present either at the base of the pistil or on the petals. These groups of cells are called
nectaries.
They attract insects such as bees and ants for cross pollination. In some cases,
nectaries are very
prominent.
Example: Nasturtium
The essential parts of a flower can be considered in two parts:
1. The vegetative part, consisting of petals and associated structures in the perianth.
2. The reproductive or sexual parts.
A stereotypical flower consists of four kinds of structures attached to the tip of a short
stalk. Each
of these kinds of parts is arranged in a whorl on the receptacle (starting from the base
of the flower
or lowest node and working upwards) as follows:
A flower can be divided as below based on the reproductive structure it has:
▪ Bisexual Flower – A flower that contains both male and female reproductive
structures is
called a bisexual flower. Bisexual flowers are also called hermaphrodites. They are
perfect
flowers.
▪ Unisexual flower – A flower that has only one reproductive structure, either male
or
female, is called a unisexual flower.
▪ Staminate flower: A unisexual flower, which contains the only androecium is
called a
male or Staminate flower.
▪ Pistillate flower: A unisexual flower, which contains the only gynoecium is called
a
female or Pistillate flower.
▪ Neuter flower: A flower in which both male and female reproductive organs are
absent is
called a neuter flower.
Sexuality in plants:
In most plants, the flowers are bisexual. They contain both male and female
reproductive parts.
In some plants, the male and female flowers are separate. These plants are of two
types—
monoecious and dioecious.
1. Monoecious plant: If the male and female flowers grow on the same plant, then the
plant
is said to be a monoecious plant. Examples: Pumpkin, Maize, Cucumber
2. Dioecious plant: If the male and female flowers grow on separate plants, then the
plant is
said to be a dioecious plant. Examples: Palm, Papaya.
Complete and Incomplete Flowers:
When all the four whorls of the flower are present, it is called a complete flower. All
bisexual
flowers are generally complete flowers.
Example: Hibiscus
Some flowers have only the male parts (Staminate) or only the female parts
(Pistillate). These are
called unisexual or incomplete flowers.
Example: papaya
Unisexual flowers may occur on the same plant at different places. These are called
monoecious
plants
Example: maize, cucumber.
If male and female flowers occur on different plants, they are called dioecious plants
, Example: palms.
Essential/ Reproductive Whorls:
The essential whorls of a flower are the whorls that are directly associated with the
process of
reproduction. A flower cannot function as a reproductive organ in the absence of
essential whorls.
Examples: Stamen and carpel.
Non- Essential/ Non-Reproductive Whorls:
The non-essential whorls of a flower are the whorls that are not directly associated
with the process
of reproduction. They are the helping parts, which either protect the reproductive parts
of the
flower or make them attractive for pollination. A plant is able to reproduce in the
absence of nonessential
whorls.
Examples: Calyx and corolla
Perianth:
In plants, such as wheat and grasses, the petals and sepals are undifferentiated and
together
compose the perianth.
Petaloid perianth: In some plants, the sepals are not green but appear brightly
coloured as the
petals. These sepals are called petaloid sepals, and the perianth is called a petaloid
perianth.
Example: Orchid
Sepaloid perianth: In some plants, the petals appear green in colour and are called
sepaloid
petals. The perianth is called a sepaloid perianth.
Examples: Viscum, Mistletoe.
Nectaries:
Nectar is a sugary liquid produced by plants. The nectar in flowers is secreted by a
group of cells,
present either at the base of the pistil or on the petals. These groups of cells are called
nectaries.
They attract insects such as bees and ants for cross pollination. In some cases,
nectaries are very
prominent.
Example: Nasturtium
The essential parts of a flower can be considered in two parts:
1. The vegetative part, consisting of petals and associated structures in the perianth.
2. The reproductive or sexual parts.
A stereotypical flower consists of four kinds of structures attached to the tip of a short
stalk. Each
of these kinds of parts is arranged in a whorl on the receptacle (starting from the base
of the flower
or lowest node and working upwards) as follows:
