The Taxonomic Consideration of Leaf Epidermal Microsturcture in Glechoma L. (Nepetinae, Lamiaceae)

Abstract

A comparative micromorphological study was examined on the leaves of the genus Glechoma and related genera (Nepetinae, Lamiaceae) by scanning electron microscopy (SEM) in order to evaluate their significance in the taxonomy. The leaves of taxa Marmoritis, Nepeta sect. Glechomanthe, G. hederacea var. longituba (Korea) are revealed amphistomatic type, while the remnants of taxa had hypostomatic type. The size range of the guard cells is 12.50-28.75 × 9.17-21.25 μm: the smallest one was found in M. pharicus (12.50-15.83 × 9.17-11.25 μm), while the largest one was measured to G. hederacea var. longituba (Korea: 28.75-28.88 × 21.25-21.38 μm). The stomatal type of genera Agastache, Dracocephalum was mostly diacytic, however for the rest rarely together with anisocytic and anomocytic, except G. hederaca var. longituba (Korea), Meehania urticifolia by having combined with diacytic and anomocytic. The shapes of epidermal cells are differ from in abaxial and adaxial side, and dived with two types (e.g., platelet, stripe pattern). Five types (three glandular, two non-glandular hairs) of trichomes are distributed in leaves. Among trichomes, long and stalk capitates glandular trichome, subsessile glands are different from studied taxa so that leaf micromorphological characters are significance features in the taxonomy.