orchid structure

The chief characteristic of an orchid flower is the column, composed of the united male and female generative organs, stamens and pistil, and bearing upon it a small button-like projection known as the rostellum, covered, like the stigma, with a sticky glue like substance attractive to insects.

Orchids are fertilised by pollen-grains falling from the anther on to the stigma, or being deposited upon it by pollen bearing insects visiting the flower. Should the rostellum be touched by an insect (or even for purposes of experiment with a pin) the pollen masses are released from the anther at the top of the column. The column often bears wing-like, semi-transparent appendages that assist in the direction of insects to the rostellum.

At the base of the column is the ovary or seed capsule.  … Read more