LIFE FORM ANALYSIS OF WEEDS FROM PADDY AGRO– ECOSYSTEM AT IMPHAL EAST, MANIPUR, NORTH – EASTERN INDIAAsha Gupta and Sophia Haobijam
Plants can be grouped in life-form classes based on their similarities in structure and function. A life-form is characterized by plant adaptation to certain ecological conditions and is an important part of vegetation description, ranking next to floristic composition. Altogether 62 species were found in the explorative survey from paddy agroecosystem and placed covering the main physiognomic structures as per Raunkier (1934) that included 34 monocot and 28 dicot species belonging to 15 families under 48 genera. The dominant families were Poaceae, Asteraceae, Cyperaceae and Amaranthaceae. In the floristic spectrum, the most represented life-forms were Chamaephytes followed by Hemicryptophytes. The percentage contribution of Poaceae was 43.55% followed by Cyperaceae and Asteraceae as 9.68% each. Chamaephytes (37.09%), Hemicryptophytes (29.04 %), Therophytes (14.52%), Cryptophytes (12.90 %) and Phenerophytes (6.45%) were the different life forms recorded. The biological spectrum was compared with Raunkiaer's 'normal spectrum' which acts as a null model against which different life-form spectra could be compared, pointing out that Chamae-Hemicrytophytic life-form characterized the phytoclimate of the agroecosystem under the present study.