XVI International Botanical Congess

The Ararat valley weed flora is consist of 413 species frame, 259 generous and 48 families that are officially registered. The correlation of large taxonomical groups is:Dicotyledonae-355 species is 85,9% and Monocotyledonae-58 species is 14,1%. On the first place, by participation in agrocoenosises and number of species, stands Compositae family (60 species, 14,5%), on the second place is Cruciferae family (44 species, 10,6%), on the third place is Gramineae family (43 species, 10,2%). From the largest genera are represented by Orobanche (10 species), Chenopodium (9 species), Cuscuta (7 species), etc.A number of new segetal and rudderal plants are discovered that were not cited in the monographic surveys of Armenian Weed Flora (Agajanian, Araratian). These new species are Ambrosia artemisifolia, Anchusa italica, Amaranthus blithoides, Buchingera axillaris, Chaenorrhinium persicum, Conyza canadensis, Galinsoga parviflora, Onagra biennis, Paspalum digitaria, Sigesbeckia orientalis, Scirpus bucharicus and many others.The analysis of the weed flora of Ararat valley together with the critical revision of published data drive to the conclusion that most of these plants have been spread here a long time ago, but they were not revealed because of the large interval in botanical investigations.