The structure of an orchid flower
Marius van Heiningen
I decided to write this post because I personally had some difficulty in finding clear pictures which explain the basal anatomy of an orchid flower. It seems that in every picture some basic parts were missing. In this entry I first give a brief summary of the basic parts of a common flower (stamen, carpel, sepals and petals), to continue with the basic parts of an orchid flower and followed by a more detailed description of the gynostemium (column). The structure of the labellum (lip) will be treated in another post because of its great complexity and diversity and its importance for indentifying the exact genera or species.
Very brief summary of a typical flower.
A typical flower has stamens, carpel(s), a whorl of sepals (calyx) and a whorl of petals (corolla).
A stamen is the pollen-producing male organ of the flower and normally consists of a threadlike filament with an anther on top. It is the anther which produces the pollen. All the stamens together are collectively called the androecium (man´s house).
A carpel is the seed-producing female organ of the flower and normally consists of an ovary, style and stigma. The ovary is the basal part of the carpel where one or more ovules are formed. The style is a stalk through which the pollen reach the ovules in the ovary. The stigma is usually on top of the style and is often sticky to capture the pollen.
In many plants the carpels are fused into one or several carpel-like structures. All the carpels together (fused or unfused) are called the gynoecium (woman´s house). In almost all flowers the gynoecium is located in the centre, surrounded by the androecium. Both are surrounded by the perianth.
The perianth is the outer part of the flower consisting of the calyx (the sepals) and the corolla (the petals). When the sepals and the petals are very similar they are called tepals.
Photo 1 shows a flower of the Turk´s cap lily (Lilium martagon) with a 6 of stamens surrounding a single style with stigma. The flower has 3 petals and 3 sepals which look very much alike (tepals).
READ FURTHER AND ENJOY
READ FURTHER AND ENJOY





