Pharmacognostical studies on adiantum plants. V. Classification based on spore morphology and distributional patterns of silicon and calcium in the ultimate pinnules

Abstract

Crude drugs derived from Adiantum species are used as febrifuge, antidote, diuretic, tonic, etc. Some commercial samples of these drugs are composed of finely cut ultimate pinnules only, which have false indusia and spores. In this paper, in order to establish a classification method based on the characteristics of the ultimate pinnules and their attachments, the morphological study using stereoscope and scanning electron microscope, and X-ray microanalysis using an electron probe microanalyzer were carried out on the false indusia and spores, and the ultimate pinnules, respectively, of 19 Adiantum species. The results showed that examined all species could be distinguished from each other by the following characteristics: in the false indusium, the shape and the presence or absence of hairs; in the spore, the shape, the ornamentation, the ratio of the laesura, and the equatorial diameter; in the X-ray images of the ultimate pinnule, the distributional patterns of silicon and calcium. The distributional patterns of silicon were due to the presence of spicular cells, hairs and papillae, and calcium was present as crystals of calcium oxalate. The average content of silicon in the ultimate pinnules of Adiantum species was 1.99%.