Grasses distribution in wheat fields of Tabriz-Iran and recorded Sclerochloa woronowii (Hack.) Tzvelev as a new weed species for flora of Iran.
In order to survey and determine the relative dominance of grassy weed species in irrigated wheat fields of Tabriz county (northwest of Iran) in 2012 and 2013, 20 and 13 grasses were observed respectively. Ermopyrum bonaepartis (Spreng.), and Alopecurus myosuroides Hudson with Relative dominance (RD) equal 153 and 90.6, respectively were dominant in 2012 and A. myosuroides, and E. bonaepartis with RD equal 128 and 102, respectively were dominant in 2013 sampling time. Between them, we found Sclerochloa woronowii (Hack.) Tzvelev as a new weed specie for Iran. This weed until nowonly was recorded for Iran neighborhood countries. This weed was only observed in Alvar sofla district of Tabriz. Uniformity in distribution, density and cover percentage of that was increased in second year. S. woronowiiis undoubtedly rather closely related to S. dura (L.) P. Beauv., but differs in the number of florets in each spikelet, rachilla articules in S. woronowii is clear but in S. dura is hidden, and S. woronowii is a slender (gracilia) gramminis but S. dura is thick-stalked (crassa) gramminis.