Botany and Plant Science

Odd petal largest  posterior and outer most called vexillum (standard). It covers two wings (Alae) which in turn covers two small, fused petals called keel (carinae.)

Anthers with two chambers are referred to as dithecous. This is a standard botanical term describing the structure of the anther lobes.

The endothecium is the layer of the anther wall that develops fibrous thickenings of callose, which help in the dehiscence of the anther to release pollen grains.

Each pistil is constructed of from one to many enrolled leaflike structures, or carpels, each of which encloses one or more ovules. The carpel is a single megasporophyll, or modified seed-bearing leaf. A pistil then may be composed of one carpel (simple pistil), as in the sweet pea, or of two or more carpels (compound pistil) partially or completely joined, as in the mustard (two carpels) or lily (three carpels). A carpel has three parts: stigma, ovary, and style. The stigma is responsible for pollination and is the top-most part of the carpel. The ovary is responsible for determining the number of carpels in a plant and is the bottom-most part of a carpel. Lastly, the style is responsible for connecting the stigma and ovary together, helping with the transfer of pollen through the carpel for pollination.

Gynoecium having a number of free carpels is called apocarpous.

The flowers belonging to the Papilionaceae family has vexillary type of aestivation in which, there is one large posteriorly placed petal called vexillum that overlaps the lateral petals called wings. These wings overlap the anterior petals that are fused to form a boat like structure called keel or carina. This type of aestivation is also called descending imbricate. These flowers also have an odd anterior sepal. They show piston mechanism of pollination. Their gynoecium is one carpel, it is monocarpellary, superior, unilocular with marginal placentation. For example, Pea, Dalbergia etc.

When ovary is lobed and the style emerges from the depressions of the lobes of the ovary, it is called gynobasic style. It is seen in the family Lamiaceae or Labiatae. 

Gynoecium with fused carpels is called syncarpous. Gynoecium with free carpels is called apocarpous.

A seed is an embryonic plant enclosed in a protective outer covering. The formation of the seed is part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiosperm plants. The maturing ovule undergoes marked changes in the integuments, generally a reduction and disorganisation but occasionally a thickening. The seed coat formed from the two integuments or outer layers of cells of the ovule, which derive from tissue from the mother plant, the inner integument forms the tegmen and the outer forms the testa

Carpel is the female reproductive organ of a flower, consisting of an ovary, a stigma, and usually a style. A carpel is the female reproductive part of the flower, interpreted as modified leaves bearing structures called ovules, inside which the egg cells ultimately form. It may occur singly or as one of a group. Fertilization of an egg within a carpel by a pollen grain from another flower results in seed development within the carpel

Transfer of pollen grains to the stigma of a pistil is called pollination. Stigma is large and feathery so that it can trap air-borne pollen grains. 

The pistils of flowers are composed of carpels which contain many ovules that have seeds inside of them. Hence, a single pistil is capable of producing more than one ovule.