ABSTRACT
<p><b>OBJECTIVE</b>To provide anatomical evidences for the morphological and histological identification of 20 medicinal species in Hypericum.</p><p><b>METHOD</b>Morphological and anatomical study on the organs of 20 medicinal species in Hypericum using tissue clearing, paraffin sectioning and thin sectioning.</p><p><b>RESULT</b>According to their anatomical characteristics, the secretory structures can be divided into nodules, secretory cavities (canals) and tiny secretory tubes of 20 medicinal species in Hypericum. Hypericin was produced and stored in the nodules, while the volatile oil was produced and stored in the secretory cavities (canals) and tiny secretory tubes. The types differed markedly from each other in location, diameter and distributional density of leaf, and the anatomical structures differed from each other of stem, calyx, petal, anther and fruit among the 20 species in Hypericum.</p><p><b>CONCLUSION</b>The secretory structures may be as anatomical evidences for the morphological and histological identification of 20 medicinal species in Hypericum.</p>