The present study focuses on Family Asteraceae is reinvestigated in various districts of Uttar Pradesh in which Conyza canadensis showing highly extensive length about 280 cm in Gorakhpur district. This species showing length about 15-90 cm in Flora of British India, 90 cm in Flora of Upper Gangetic Plain, 30-70 cm in Flora of Madhya Pradesh and 15-90 cm in Flora of India. During the floristic investigation this species are collected from different regions of Uttar Pradesh. This species was identified on the basis of morphological, anatomical and floral characters. A taxonomic account of C. canadensis has been given along with their current valid name, flowering and fruiting, habit, locality and specimen voucher number.