Column (botany)

Flower of Stylidium turbinatum, showing the column.

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

It is derived from the fusion of both male and female parts (stamens and pistil) into a single organ. This means that the style and stigma of the pistil, with the filaments and one or more anthers, are all united.


Longitudinal view of a vanilla flower, showing the column

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).

This stigma has the form of a small bowl, the clinandrium, a viscous surface embedding the (generally) single anther. On top of it all is the anther cap. Sometimes there is a small extension or little beak to the median stigma lobe, called rostellum.

Column wings may project laterally from the stigma. The column foot is formed by the attachment of the lip to the basal protruding part of the column. One speaks of a mentum (chin) if the lateral sepals are also basally adnate (= attached to the foot of the column).

The column both releases pollen and also receives it (from another individual) for fertilization. In the Orchidaceae family, 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.

Wikimedia Foundation. 2010.

Look at other dictionaries:

  • Column (disambiguation) — A column is a vertical structural element in architecture. Column may also refer to: Column (botany) or gynostemium, a part of an orchid Column (database), a set of data values of a particular type in a relational database Column (formation), a… …   Wikipedia

  • column — /ˈkɒləm / (say koluhm) noun 1. Architecture a. an upright shaft or body of greater length than thickness, usually serving as a support; a pillar. b. a vertical architectural member consisting typically of an approximately cylindrical shaft with a …   Australian English dictionary

  • torus —   n. (pl. ri ) rounded swelling; Architecture, such lowest moulding of column;   Botany, receptacle; Geometry, ring shape as of quoit or doughnut formed by rotation of a circle about an axis in its own plane.    ♦ toric, a …   Dictionary of difficult words

  • cohesion hypothesis — ▪ botany       in botany, a generally accepted explanation of the rise of sap in plants by means of intermolecular attractions. Calculation and experiment indicate that the forces of cohesion between water molecules and the forces of adhesion… …   Universalium

  • Life Sciences — ▪ 2009 Introduction Zoology       In 2008 several zoological studies provided new insights into how species life history traits (such as the timing of reproduction or the length of life of adult individuals) are derived in part as responses to… …   Universalium

  • Stylidium — Taxobox name = Stylidium image caption = Flower of Stylidium graminifolium image width = 220px regnum = Plantae divisio = Magnoliophyta classis = Magnoliopsida ordo = Asterales familia = Stylidiaceae genus = Stylidium genus authority = Sw. ex… …   Wikipedia

  • Bifrenaria — tyrianthina Scientific classification Kingdom: Plantae …   Wikipedia

  • angiosperm — /an jee euh sperrm /, n. Bot. a plant having its seeds enclosed in an ovary; a flowering plant. Cf. gymnosperm. [ANGIO + SPERM] * * * ▪ plant Introduction       any member of the more than 300,000 species of flowering plants (division Anthophyta) …   Universalium

  • Glossary of botanical terms — Many of the terms used in Wikipedia glossaries (often most) are already defined and explained within Wikipedia itself. However, lists like the following indicate where new articles need to be written and are also useful for looking up and… …   Wikipedia

  • Mikhail Tsvet — Born 14 May 1872(1872 05 14 …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.