Column (botany)

The column, or technically the gynostemium, is a reproductive structure that can be found in several plant families: Aristolochiaceae, Orchidaceae, and Stylidiaceae.

The stigma sits at the apex of the column in the front but is pointing downwards after resupination (the rotation by 180 degrees before unfolding of the flower).

[citation needed] This stigma has the form of a small bowl, the clinandrium, a viscous surface embedding the (generally) single anther.

In the family Orchidaceae, unlike almost all other flowering plants, the single male anther at the tip of the column produces pollen that is not free and powdery but held in waxy masses of two, four or six pellets called pollinia.

The transfer of pollinia from one flower to another, though highly efficient, is often reliant upon one particular species of arthropods and it can be catastrophic for the population if its pollinator disappears from the community.