Tuesday, 30 June 2009

Basic about Flower - Symmetry

Floral symmetry refers to whether, and how, a flower can be divided into 2 or more identical or mirror-image parts.

Most flowers are actinomorphic, meaning they can be divided into symmetrical halves by more than one longitudinal plane passing through the axis. Examples are flowers of Liliaceae, Ranunculaceae.


However, some familiar and seemingly actinomorphic flowers, such as those from Asteraceae, are actually clusters of tiny zygomorphic flowers arranged into a radially symmetric inflorescence.


Zygomorphic flowers can be divided by only a single plane into 2 mirror-image halves. Examples are flowers of Zingiberales, Lamiales ( Scorphulariaceae, Gesneriaceae )


Actinomorphic flowers are basal angiosperm character ; zygomorphic flowers are a derived character that has evolved many times.

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