Some observations on the weed flora of rice fields in the Nile Delta, Egypt

The weed flora associated with field crop of rice in five governorates in the Nile Delta was studied. The weed association comprised 71 species related to 28 families (23 dicot families, five monocot families).The recorded species formed of 28 monocot species (39.4%), 42 dicot species (59.2%), and only one pteridophyte (1.4%). By using TWINSPAN technique the recorded weeds of 25 stands are grouped into six weed clusters. The weed clusters are superimposed on DCA axes 1 and 2 with respective eigene values of 1.00 and 0.964. The ordination plane shows that weed clusters are clearly separated along DCA‐axis 2. These clusters are named after the dominant species as follows: Aster squamatus, Corchorus olitorius, Echinochloa crus‐galli – Echinochloa colona, Amaranthus hybridus – Amaranthus viridis, Ammannia baccifera – Abutilon theophrasti and Ammannia attenuata – Anagallis arvensis . The therophytes represent 57.8% of the life form spectrum, while perennials represent 42.2%.