In the present study the top down approach has been utilized to quantify homogeneity of ethno-knowledge, frequency of species utilized for a disease related to a specific system as well as identification of corporeal system that are outliers with aim to identify the species and their usefulness for a specific disease that make the system as outlier. The study was carried out for medicinal plants of arid and semiarid region of the Indian Thar area. Three statistical parameters namely, evenness, frequency distribution and regression and residual value analysis were utilized. The study revealed that ethno-medicinal knowledge about 136 species were related with 12 different corporeal systems and frequency distribution classified these 136 species and 12 corporeal systems under 9 different classes. Maximum numbers of taxa are recorded for skeletal, muscle and connective tissues (114) followed by the digestive system (111) and skin and sub-cutanuous system (89). Homogeneity of ethnic- knowledge are restricted for few corporeal systems like respiration, fever, blood and hematopoietic organ, central nervous system, genito-urinary system and circulatory systems, while random and clumped types knowledge distribution were recorded for other corporeal systems. Platykurtic and leptokurtic types of distributions were observed for different corporeal systems. Through use of standard residuals analysis of medico-ethnic-knowledge, digestion system was designated as positive outliers while fever and genito-urinary systems were the negative outliers. Further regression analysis has revealed that with in this region ethnic knowledge about the medicinal properties of a species is largely associated with the regional abundance of taxa
