The androecium is the male reproductive whorl individual unit of which is stamen. Each stamen consists of fertile anther joined with filament with the help of connective tissue. Anther may be single lobed or bilobed in nature. Single lobed anther is known as monothecous anther and two lobe anther is known as dithecous anther.
fig:Attachment of anther and filament
The filament is attached to the base of the anther.
It is also basifixed type in which the connective runs throughout the length of anther and protrudes out from the apex.
The filament is attached to the dorsal surface of another.
Filament just touches the dorsal side of another so that the anther can easily swing.
fig:Length of stamens
The presence of 4 stamens, 2 with short filaments and 2 with long filaments. Eg; Ocimum ((Tulsi).
The presence of 6 stamens in two whorls, outer 2 with short filaments and inner 4 with long filaments. Eg; Cruciferae
If the stamens are free, the condition becomes polyandrous as the stamen has two parts, the cohesion or fusion of stamens occur in different ways which can be categorized into three conditions:
Anther is fused, a filament is free. Eg; Compositae
In this, the filament is fused and anther is free. It is of three types they are:
Filaments fused into a single bundle or staminal tube. Eg; Hibiscus
Filaments fused into two bundles. Eg; Pisum
Filaments fused to form more than two bundle. Eg; Rosa
In this type, the stamens are completely fused.
Epipetalous: Stamens( filaments) attached with the petals.
Gynandrous: Stamens (filaments) attached with the gynoecium.