Page 47 - Pharmacognosy-I (02-06-06-102)
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The stamens may be sterile i.e. not producing pollen grains
and termed staminode. Also the anther may be sessile if the
filaments are absent. The stamens in each flower are all alike and
most commonly of equal length but they may differ in length.
Accordingly, the androecium is described as:
a- Didynamous: when formed of two long and two short stamens
e.g. Labiatae.
b- Tetradynamous: when formed of four long and two short
stamens e.g. Cruciferae.
Cohesion of staments:
It is the union of the stamens together. Stamens may be free or
united; they may be united through the filaments only with free
anthers or through the anthers with free filaments.
The terms denoting the way of fusion of the stamens together
with free anthers are:
a- Monadelphous: when filaments are fused in one group.
b- Diadelphous: when filaments are fused in two groups.
c- Tri-tetra-or polyadelphous: when filaments are fused in
three, four or more groups.
When the filaments are free but the anther are united the stamens
are described as syngenesious e.g. Asteraceae.
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