Morphological comparison of Ambrosia psilostachya in different habitats of Bandar-Anzali (Guilan province, north of Iran)

This study was done to compare the plant morphology of Ambrosia psilostachya DC. (ragweed) in four habitats of roadsides (1), paddy field margins (2), around residential areas (3) and coastal areas (4) in Bandar-e Anzali (Guilan province, north of Iran) in 2019. Sampling was random in five growth stages with 10 plants in each habitat. The results indicated that, the highest biomass, plant height and inflorescence length was in the habitats of (2) & (4), and the highest inflorescence numbers was in (3) & (2). The maximum plant biomass in the habitats of (2), (1) & (4) was 110 days, and in (3) was 82 days after the emergence and then the plant entered the reproductive phase. The trend of plant height increased in the habitat of (1) continued up to 69 days, and in (2) & (4) continued up to 110 days after emergence and then decreased while in habitat of (3), the trend was linear and continued until November. The beginning of flowering was in mid-July in all habitats. The increasing trend of number of flowering stems in habitats of (3) & (4) was up to 82 days after emergence, but in (2) & (1) had a linear trend and continued until November.