Lehtireunan

Lehtireunan refers to the outer edge of a leaf and is a standard descriptor in plant morphology. In botanical descriptions it is used to characterize the leaf margin, one of several features that help identify species and understand leaf form. The margin is typically described in relation to its contour, presence of teeth or lobes, and degree of indentation, and it is often reported alongside leaf shape, venation, and surface texture.

Common margin forms include several broad categories. An entire or smooth margin has no teeth or lobes along the edge. Serrate margins show teeth pointing forward, like a saw. Dentate margins have teeth pointing outward, while crenate margins display rounded teeth. Serrulate margins are finely toothed, and lobed margins feature distinct indentations that form lobes. More deeply dissected margins may be described as cut or incised. Many leaves can also exhibit undulate (wavy) or irregular margins, which botanists distinguish from the natural margin form.

The margin type is not only descriptive but can have ecological and evolutionary relevance. Margin variation occurs among species and can reflect genetic differences, developmental processes, and adaptations to environmental conditions. In field guides, herbarium records, and taxonomic revisions, lehtireunan is frequently cited as a key character for distinguishing taxa and documenting leaf diversity within a genus or family. Researchers typically examine multiple leaves to capture intra-individual variation and ensure accurate descriptions.