Abstract [Objective] This study was conducted to investigate the microscopic identification characteristics of Jatropha curcas. [Methods] Jatropha curcas was identified by microscopic identification. [Results] The stem bark of J. curcas has a thick phellem layer and broad cortex layer； and there are a great deal of dispersed laticifers and many fibers. The parenchymal cells contain clusters of calcium oxalate. In the powder， there are many clusters of calcium oxalate； the secreta is often dispersed； and the stomata are in parallel axle shape. Brown bodies can be seen commonly. [Conclusion] The results of the microscopic identification are reliable. These characteristics could provide an effective basis for the differentiation of this plant from other plants in the same genus and the establishment of its quality standard.
　　Key words Zhuang medicine； Jatropha Curcas.； Identification
　　Jatropha curcas L.， belonging to Euphorbiaceae family， is also known as Chouwutong， Jiahuasheng， Jiatongzi and Liangtong. J. curcas has wide medicinal application according to the recordings in Color Graphs of Common Chinese Medicinal Herbs， Chinese Medicinal Herbs in Guangxi and selection of Chinese medicinal herbs in Simao City of Yunnan Province[1].
　　J. curcas trees are mostly cultivated， and distributed in many provinces in China， mainly in Yunnan Province， which has the largest distribution area and the largest resource number[2]. In Guangxi Province， it is mainly distributed in Qinzhou， Rong County， Nanning， Baise， and Du??an[3]. In this study， the microscopic characteristics of J. curcas was identified， laying a foundation for the formulation of the quality control standards of J. curcas.
　　Materials and Instruments
　　Experimental materials
　　The J. curcas material was collected from Dujie Township， Longan County. It was identified by professor Wei from Guangxi Medical University as the bark of J. curcas in Euphorbiaceae family.
　　Instruments
　　Sartorius BS214D electronic analytic balance （Sartorius Scientifc Instruments （Beijing） Co.， Ltd.）； DF??20 table type continuous feeding pulverizer （wenling linda machinery co.， ltd.）； HH??4 digital thermostat water bath （Changzhou Guohua Electric Appliance Co.， Ltd.）； 101A??3E electrothermal blowing dry box （Shanghai Test Instruments Co.， Ltd.）； SX2 chamber electric furnace （Shanghai Test Instruments Co.， Ltd.）； SK2200LHC ultrasonic cleaner （shanghai Kudos Ultrasonic Instrument Co.， Ltd.）； DM??2500M biological microscope （Leica Instruments Co.， Ltd.）. 　　Methods and Results
　　Experimental methods
　　The J. curcas part with a diameter of 3-10 mm was selected and prepared by paraffin section method， and prepared into a permanent slide through double staining. In order to prepare a powder slide， the stem and leaf sample was dried， pulverized and sieved with a 60??mesh sieve， and the slide was prepared with dilute glycerol. The slides were observed under a DM2500M biological microscope， and photographed with an imaging system.
　　Bark transection The phellem layer is thick and composed with more than ten columns of cork cells， which are rectangular in close arrangement， and form a falling layer easily. The phelloderm is obvious with multiple columns of cells. The cortex layer is broad and occupies the most part of the transection. There are many dispersed laticifers， the cells around which are closely arranged， forming a polygon. There are multiple fibers which form bundles or are dispersed in single form. There is narrower phloem at the internal side. The parenchyma cells contain clusters of calcium oxalate. The image is shown in Fig. 1.
　　Powder characteristics The powder is brown. There are few starch granules， which are quasi??circular， in the shape of an umbilical point， with a diameter of 14-34 ??m. There are abundant clusters of calcium oxalate， with sharp corner angles， having a diameter of 12-82 ??m. In the broken tissues， laticifers could be observed， containing yellowish??brown secretion， which is often dispersed. The vessels are mostly spiral vessels， rarely reticulate vessels， with a diameter of 20-185 ??m. The fibers mostly form bundles or are dispersed in single form， with thick cell wall， having a linear cell shape. The stomata are in parallel axle shape. Brown bodies can be seen commonly. The image is shown in Fig. 2.
　　Discussion
　　To sum up， the bark of J. curcas trees has obvious microscopic features. It could be seen from the microscopic characteristics of Zhuang medicine J. curcas that the stem bark of J. curcas has a thick phellem layer and broad cortex layer； and there are a great deal of dispersed laticifers and many fibers. The parenchymal cells contain clusters of calcium oxalate. In the powder， there are many clusters of calcium oxalate； the secreta is often dispersed； and the stomata are in parallel axle shape. Brown bodies can be seen commonly. These characteristics could provide an effective basis for the differentiation of this plant from other plants in the same genus and the establishment of its quality standard.
　　References
　　[1] State Administration of Traditional Chinese Medicine. Chinese materia medica[M]. Shanghai： ShanghaiScientific and Technical Publishers， 1999.
　　[2] YANG SL， FAN YQ， SHA YC， et al. Distribution and integration exploitation utilize foregroud of Jatroph curcas L. resource[C]//Outstanding paper selections of Botanical Society of Yunan China in 2004-2006， 2006： 6.
　　[3] LIU FY， LI K， SUN YY. Research development and utilization status on Jatrophacurcas in China[J]. Journal of China Agricultural University，2012，06：178-184.