'Bulrush' in the Bible

So the Lord cuts off head and tail from Israel,Both palm branch and bulrush in a single day.

There will be no work for EgyptWhich its head or tail, its palm branch or bulrush, may do.

Is it such a fast that I have chosen? a day for a man to afflict his soul? is it to bow down his head as a bulrush, and to spread sackcloth and ashes under him? wilt thou call this a fast, and an acceptable day to the LORD?