bladmarger

Bladmarger, or leaf margins, refer to the edge or border of a leaf blade in plants. In botany, the margin is a key feature used in species descriptions and dichotomous keys alongside leaf shape, size, venation, and texture. Margin terms convey how the leaf edge appears to the eye and under light magnification, aiding identification and comparison across taxa.

Common margin types include entire, serrate, dentate, serrulate, crenate, crenulate, lobed, undulate, revolute, and involute, with occasional distinctions such as incised or pinnatifid margins. An entire margin is smooth without teeth or indentations. Serrate margins have saw-like teeth with pointed tips facing toward the leaf apex. Dentate margins show teeth that are generally more upright or triangular. Serrulate describes very fine serrations, while crenate margins possess rounded teeth. Crenulate margins are even finer and more closely spaced. Lobed margins display deeper indentations forming distinct lobes. Undulate margins exhibit a wavy outline. Revolute margins have edges rolled backward toward the underside, whereas involute margins roll inward toward the upper surface. Some margins are deeply incised or divided, producing pinnatifid or dissected appearances.

Margins can vary within a species due to developmental stage, leaf position, or environmental conditions, so descriptions often note typical or observed variations. In practice, leaf margin terminology is used in floras, field guides, and herbarium specimens to support identification and comparative taxonomy, complementing other leaf and plant characters.