Biology and ecology.

Abstract This chapter provides comprehensive information on the overall biology and ecology of parthenium weed (Parthenium hysterophorus). It provides specific details on the taxonomy, plant distinguishing characteristics, its likely centre of origin, genetics and intraspecific diversity, growth, reproduction and phenology, seed biology (including seed production, dispersal, dormancy, germination, longevity and seed bank), population dynamics and preferred climatic requirements for growth. The chapter also highlights how various biological and ecological characteristics of parthenium weed, such as its morphological attributes, biological plasticity, intermediate photosynthesis mechanism, allelopathy, stress tolerance, competitive ability and long-lived seeds, make it one of the most successful global invasive species.