Abstract: Differing biomass allocation strategy could be a necessary plant-trait associated with invasive weeds in an alien environment. The present study focused on exploring differential biomass allocation pattern as an invasive plant-trait in the two pantropical invasive malvaceous weeds Sida acuta Burm f. and Sida cordifolia L. in an anthropic peri-urban vegetation in Indian dry tropics. Eighty plant individuals from each of these two congeners across their varying developmental stages were clipped off from their dominantly growing study site at the polluted bank of Kali river in Bulandshahr (28º04’ & 28º43’ N lat. and 77º08’ & 78º28’ E long.) in the national capital region of India.