THE STUDY OF ACTIVE INGREDEENTS ON 8 TRADITIONAL CHINESE MEDCINES BY THE BRINE SHRIMP LETALITY BIOASSAY Chemical constituents from roots of Pteroxygonum giraldii Reappraisal of the generic status of Pteroxygonum (Polygonaceae) on the basis of morphology, anatomy and nrDNA ITS sequence analysi Chemical Constituents of the Essential Oils of Pteroxygonum giraldii and Polygonum amplexicaule