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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 termed sympetalous).
Perianth --the calyx and corolla together
Stamen --one 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 stamen.
Each stamen consists of a filament and anther , where pollen is produced. Collectively, the stamens make up the androecium androecium
1. Tetradynamous - refers to four long and two short stamens in one flower Types of Stamens
2. Monadelphous --refers to stamens united by the filaments into one column
3. Diadelphous --refers 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 gynoecium .
- Each carpel consists of an ovary connected to a
s tigma 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 septa .
Carpel = inserted above the stamens,
= uppermost floral organ
= consist of Stigma, Style and Pistil
which is collectively called
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 pistils
- A gynoecium of many separate carpels
= A gynoecium of many fused carpels
= The flower is said to have a compound pistil
In the very center of the flower is a single carpel . A carpel is the basic unit of a gynoecium.
This flower only has one carpel , and flowers like this are said to have a monocarpous gynoecium .
- gynoecium with only one carpel
- The flower has a simple pistil
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.
1. Hypogynous --The flower is hypogynous if the ovary is situated above the calyx and there is no floral cup around it. The ovary is superior .
-The flower is perigynous if the ovary is situated within (and free from) a floral cup or hypanthium . The ovary is superior .
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 down.)
An inflorescence may be defined as a cluster of flowers, all flowers arising from the main stem axis or peduncle :
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 willow.
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
--just one flower on the peduncle
- is the characteristic inflorescence of the remarkable arum family (Araceae).
- 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 vase-shaped 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 pollination.
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).
- This inflorescence has an unbranched main axis and all the pedicels of the flowers are more or less the same length.
Other raceme Sweet pea ( Lathyrus odoratus ) Chinese hat ( Holmskioldia sp. )
- The peduncle of this type of inflorescence bears all of the pedicels at its apex.
- The peduncle bears a number of primary pedicels at its apex. These do no bear flowers but a number of secondary pedicels at their apices which in turn bear the flowers.
Frangipani ( Plumeria rubra )
- This inflorescence type has a long, unbranched main axis which bears flowers which have no pedicels or very short pedicels.
Silver oak ( Grevillea robusta )
Quiver tree ( Aloe dichotma ) Gladiolus ( Gladiolus sp. ) Red hot poker ( Kniphofia sp. ) Quiver tree ( Aloe dichotma ) Quiver tree ( Aloe dichotma ) Quiver tree ( Aloe dichotma ) Quiver tree ( Aloe dichotma )
- 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.
Examples: King protea ( Protea cynaroides ) Daisy species
Mimosa sp. Pincushions ( Leucospermum sp. )
- 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 flat-topped. Examples include hawthorn, the apple and dogwood.
hawthorn Hydrangea corymb (group of flowers displayed as a disc)
Difference of corycomb, cyme and umbel
-like a spike, but with the flowers and inflorescence subtended by specialized bracts. Usually applied to the grass family (Poaceae)
Verticil or Whorl-
-the flowers are borne in a tight circle at each node
--the main axis has branches which are in turn rebranched