Microscopic identification of Tibetan medicinal herb "Songdi" (Saxifraga umbellulata var. pectinata)

To establish a method of microscopic identification of Tibetan medicinal herb " Songdi" (Saxifraga umbellulata var. pectinata).The different characteristics and microscopic identification of 4 species of Songdi were compared, including the main variety (Saxifraga umbellulata var. pectinata ) and approximate varieties (S. unguiculata, S. przewalskii and S. tanguTi,) were studied and compared.The botanical anatomy characteristics of Saxifraga umbellulata var. pectinata (including roots, stems, leaves, flowers, stalks and fruits) have been measured. The methods for powder identifications and transverse section of stems root and leaves of four species of Songdi were established.Four species of Songdi can be identified by the growth pattern of basal leaves, type of hair, type of inflorescence, number of flowers, proportion of tissue structures in stem, form of pollen grains.