`color{blue} ul(mathtt ("Aestivation"))`: The mode of arrangement of sepals or petals in floral bud with respect to the other members of the same whorl is known as aestivation.

The main types of aestivation are valvate, twisted, imbricate and vexillary.

`star` `color{Brown}"Valvate"` : When sepals or petals in a whorl `color{Violet}"just touch one another"` at the margin, `color{Violet}"without overlapping"`, it is said to be `color{Violet}"valvate"`.
E.g.: Calotropis

`star` `color{Brown}"Twisted"` : If one margin of the appendage `color{Violet}"overlaps"` that of the next one and so on, it is called `color{Violet}"twisted"`.
E.g.: China rose, lady’s finger and cotton

`star` `color{Brown}"Imbricate"` : If the margins of sepals or petals `color{Violet}"overlap"` one another but `color{Violet}"not in any particular direction"`, the aestivation is called `color{Violet}"imbricate"`.
E.g.: Cassia and gulmohur

`star` `color{Brown}"Vexillary/Papilionaceous"` : In this, there are five petals, the largest (`color{Violet}"standard"`) overlaps the two lateral petals (`color{Violet}"wings"`) which in turn overlap the two smallest anterior petals (`color{Violet}"keel"`); this type of aestivation is known as `color{Violet}"vexillary or papilionaceous"`.
E.g.: Pea and bean flowers

● `color{Brown}"Members"` : Androecium is composed of `color{Violet}"stamens"`.

● `color{Brown}"Parts"` :
`star` Each stamen which represents the male reproductive organ consists of a `color{Violet}"stalk or a filament"` and an `color{Violet}"anther"`.

`star` Each anther is usually `color{Violet}"bilobed"` and each lobe has two chambers, the `color{Violet}"pollen-sacs"`.

`star` The `color{Violet}"pollen grains"` are produced in pollen-sacs.



● A `color{Violet}"sterile"` stamen is called `color{Violet}"staminode"`.

● `color{Brown}"Types Based on"` :

`star` Stamens of flower may be `color{Violet}"united"` with other members such as petals or among themselves.

● `color{Brown}"Epipetalous"` : When stamens are attached to the petals, they are `color{Violet}"epipetalous"`. E.g.: brinjal

● `color{Brown}"Epiphyllous"` : `color{Violet}"Epiphyllous"` when attached to the perianth as in the flowers of lily.

● `color{Brown}"Polyandrous"` : The stamens in a flower may remain free.

● They may also be united in varying degrees.
`star` `color{Brown}"Monoadelphous"` : The stamens may be united into `color{Violet}"one bunch"` as in china rose.

`star` `color{Brown}"Diadelphous"` : United into `color{Violet}"two bundles"` as in pea.

`star` `color{Brown}"Polyadelphous"` : United into `color{Violet}"more than two bundles"` as in citrus.

● `color{Brown}"Members"` : Gynoecium is made up of one or more carpels.

● `color{Brown}"Function"` : It is the female reproductive part of the flower.

● `color{Brown}"Parts"` : A carpel consists of three parts namely `color{Violet}"stigma"`, `color{Violet}"style"` and `color{Violet}"ovary"`.

`star` Ovary is the `color{Violet}"enlarged basal part"`, on which lies the elongated tube, the style.

`star` The style connects the ovary to the stigma.

`star` The stigma is usually at the `color{Violet}"tip"` of the style and is the `color{Violet}"receptive surface"` for pollen grains.

`star` Each ovary bears one or more `color{Violet}"ovules"` attached to a `color{Violet}"flattened, cushion-like placenta"`.

`star` After `color{Violet}"fertilisation"`, the ovules develop into `color{Violet}"seeds"` and the ovary matures into a `color{Violet}"fruit"`.



● Types: Based on state of carpels
`star` `color{Brown}"Apocarpous"` : When more than one carpel is present, they may be `color{Violet}"free"` as in lotus and rose; and are called `color{Violet}"apocarpous"`.

`star` `color{Brown}"Syncarpous"`: They are termed `color{Violet}"syncarpous"` when carpels are `color{Violet}"fused"`, as in mustard and tomato.

`color{blue} ul(mathtt ("Placentation"))`: The arrangement of ovules within the ovary is known as placentation.

The placentation are of different types namely, marginal, axile, parietal, basal, central and free central.

● `color{Brown}"Marginal"`: In `color{Violet}"marginal placentation"` the placenta forms a `color{Violet}"ridge along the ventral suture"` of the ovary and the ovules are borne on this `color{Violet}"ridge"` forming two rows, as in pea.



● `color{Brown}"Axile"`: When the placenta is `color{Violet}"axial"` and the ovules are attached to it in a `color{Violet}"multilocular ovary"`, the placentation is said to be`color{Violet}" axile"`, as in china rose, tomato and lemon.



● `color{Brown}"Parietal"`: In `color{Violet}"parietal placentation"`, the ovules develop on the `color{Violet}"inner wall of the ovary"` or on peripheral part. Ovary is `color{Violet}"one-chambered"` but it becomes two chambered due to the formation of the `color{Violet}"false septum"`, e.g., mustard and Argemone.



● `color{Brown}"Free central"`: When the ovules are borne on `color{Violet}"central axis"` and `color{Violet}"septa are absent"` , as in Dianthus and Primrose, the placentation is called `color{Violet}"free central"`.



● `color{Brown}"Basal"`: In `color{Violet}"basal placentation"`, the placenta develops at the`color{Violet}" base of ovary"` and a `color{Violet}"single ovule"` is attached to it, as in sunflower, marigold.