Biomass and inflorescence number of Kyllinga brevifoliawere surveyed in Hiroshima Prefecture,Japan (34°18' to 25' N, 132°26' to 45' E) and in Malang, Indonesia (7°44' to 8°26' S, 112°12' to 57'E) to gain understanding of its survivorship in temperate and tropical regions. Monthly observationswere conducted by using 1 m2plots of six study sites in Hiroshima from April 2000 to April 2001 whileobservations in Malang were carried out in ten study sites four times a year from March 2000 to March2001. Considering to developmental stages in the temperate zone, the growing period of K. brevifolia started in the early of April as the beginning of bud sprouting and vegetative development. The genera-tive organ started to appear in the end of May and the first matured seeds occurred in the last week ofJune. The growing period of K. brevifoliaunderwent until December 2000 with a peak in August. Theinflorescences appeared from May to December where its maximum number was in October. Averagedaily temperature was significant correlated with the biomass pattern (r2=0.792). On the other hand, inthe tropical region this plant grew and flowered throughout the year with peaks of biomass and inflores-cence number were in the end of the rainy season (March 2000/2001). The inflorescence number wasminimum in the dry season (July 2000) while the lowest biomass occurred in the early rainy season(November 2000). Furthermore, the pattern of average daily precipitation appeared to be most similarwith the flowering pattern. These diverse patterns of productivity and flowering of K. brevifoliamayexplain a great adaptation of this weed to different climate across the regions.