The methods of field investigation,specimen collection,classification and literature retrieval have been employed to validate there are ten species of dysosma.The authors emend the list and give a brief description of the biological features and zoological-geography distribution of Dysosma Woodson.

The anatomical structure of seven species of Dysosma has been researched in this paper,and D.tsayuensis、D.guangxiensis and D.maiorensis are frist reported.In the result,we have found the parenchyma of cortex has crystal,starch grain,etc,the endodermis has evidenced,and the vascular type is tetarch,pentarch and hexarch.D.difformis、D.veitchii、D.versipellis and D.guangxiensis have corkification in the pith.The anatomical characters of roots could be used to circumcribe the species within Dysosma as they are stable among different species.

There exist in Xiaozhaizigou National Nature Reserve,Sichuan Province,36 species of pteridophytes,which belong to 21 genera of 16 families.According to potency,it could be divided into 10 types,such as medicines for cleaning away heat or anti-rheumatism,medicines for inducing diuresis,medicines for expelling the parasites,hemostasis medicines,medicines for activating blood circulation to remove blood stasis,medicines for calming the liver to stop the wind,etc.This paper puts forward some suggestions for exploitation,utilization and protection of the medicinal pteridophytes in this area.

The research progress on utilization of Alternanthera philoxeroides(Mart.)Griseb at present was summarized.