Flag Two Hebrew words:
(1) cuph (Exodus 2:3, Exodus 2:1, "flags"; Isaiah 19:6, "flags"; Jonah 2:5, "weeds"). This is apparently a general name which includes both the fresh-water weeds growing along a river bank and "seaweeds." The Red Sea was known as Yam cuph.
(2) 'achu (Genesis 41:2, Genesis 41:18, the King James Version "meadow," the Revised Version (British and American) "reed-grass"; Job 8:11, "Can the rush grow up without mire? Can the flag (margin "reed-grass") grow without water?"). Some such general term as "sedges" or "fens" would better meet the requirements.