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How can bilaterally symmetric flowers help identify many Lamiales plants?
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Lamiales
The lilac-pink flowers of the water mint attract butterflies and beetles.
Many plants in the Lamiales order can be identified by their bilaterally symmetric, or zygomorphic, flowers. This means the corolla is irregularly shaped and can be divided into two equal halves by only one longitudinal plane.12
Key features of these flowers that aid in identification include:
- Two-lipped structure: The corolla often forms two distinct lips, typically composed of two petals on the upper lip and three on the lower.1
- Reduced stamen count: These flowers generally possess fewer stamens than petals. While they may derive from a five-part plan, most species exhibit only two or four functional stamens due to the suppression of others.1
- Specialized appendages: Some species feature a pronounced "palate" on the lower lip that can close the corolla throat, or a backwardly projecting spur at the base of the corolla used for nectar production.1
- Epipetaly: The stamen filaments are typically united with the petals, a condition known as epipetaly.1