A Phytosociological study on the weed vegetation of fields in Damghan

The weed phytosociology in Damghan fields، have been studied using the method of Braun- Blanquet. 198 releves have been taken from 28 fields and 19 releves have been deleted due to fimilarity with the others، and phytosociological data analysis on 149. Remained releves were been done according to the C. A. H (Classification Ascendante Hierarchique) and A. F. C. (Analyse Factorielle des Correspondance) methodes. 22 associations and subassociations have been defined. Weeds are mainly therophyte (47/5%) and hemicryptophyte (32/8%). Geophytes are less frequent (9/83%). Cosmopolitan elements are 39/3%، Irano-Turanian 22/9% and the rest are pluriregional.