Unlike many other commercially important herbs that have had their microscopic features described in monographs or textbooks, illustrated descriptions forGinkgo bilobaL. leaves are not readily available. This paper presents an illustrated review of the most characteristic microscopical features of the leaves. The dried, powdered petiole and lamina of ginkgo leaves harvested at three different points in the annual growth cycle of the plant (spring, late summer, and fall) were examined using light microscopy at 100× to 1,000× magnification and photographed. The main characteristic features of the lamina were found to be wavy walled epidermal cells, anisocytic stornata, calcium oxalate cluster crystals, a marked cuticle, lignified vessel elements, and, rarely, uniseriate elongated trichomes. With the exception of epidermal cells and stomata, similar features were observed in the petiole, although vessel elements formed a greater proportion of the tissue and extremely rare starch grains were also observed. The shape of the epidermal cell wall, size of calcium oxalate crystals, and appearance and extent of lignification of vessel elements were found to vary with the developmental stage of the leaf. The occurrence of yellow globular material within the cells of the leaf appeared to increase with age. The nature of the material was not elucidated, but chemomicroscopic examination suggested that it was not composed of starch, phenolic substances, or oils. It is anticipated that the present publication will serve as a useful, illustrated description of the microscopical features of ginkgo leaf and provide a guide to preparing suitable slides for evaluation of botanical sample
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