ABSTRACT
Data collected during our on-going studies on the phytodiversity in the Upper Bari Doab Region of Punjab, show an inverse relationship between the level of phytodiversity and incidence of the congress grass-Parthenium hysterophorus. The open vegetation at Khiala Khurd (31 degrees -33' N-74 degrees .18' E), a site typical of the whole region, has a Shannon-Weaver index value of 2.544, which is fairly good for any dry tropical area. At this site the weed has an insignificant presence (IVI = 0.834%). In contrast, at Fatahpur (31 degrees .33' N-74 degrees .21' E), a site bereft of vegetation, it is the dominant species with an IVI of 79.1%. The corollary emerges that restoration of a natural cover of vegetation is the best strategy to check the weed. However, for replantation, the choice of species depends on the combination of climatic and edaphic factors obtaining at a location.