RUSH (אַגְמוֹן, H109, גֹּ֫מֶא, H1687). The word “rush” can equally well be tr. “reed” either as agmôn or gōme. In Isaiah 9:14 (KJV) and 19:15, the word agmôn is used, while in Job 8:11 and Isaiah 35:7, the word gōme appears. The term “rush” therefore seems intimately confused with “reed.”
The problem is increased because there are a large number of different species of rush growing in Pal. There are fifteen different types of club rush, e.g. Scirpus maritimus and Scirpus lacustris, and some twenty types of the common rush, Juncus maritimus, which are found at the seaside. There is also Juncus effusus, found in the bogs and wet places.
International Standard Bible Encyclopedia (1915)
(1) (gome’; papuros, "bulrushes," margin "papyrus" (Ex 2:3); "rush," margin "papyrus" (Job 8:11); "papyrus," the "rush" (Isa 18:2); "rushes" (Isa 35:7)): This is almost certainly the famous papyrus, Cyperus papyrus (Natural Order, Cyperaceae), known in Arabic as babir (whence comes our word "paper"). This plant, the finest of the sedges, flourishes plentifully in Upper Egypt; in Palestine there is a great mass of it growing in the marsh to the North of Lake Huleh, and it also occurs on the Lake of Galilee and the Jordan. Light boats of plaited papyrus have been used on the Nile from ancient times and are mentioned by many writers (compare Ex 2:3; Isa 18:2).
(2) (’aghmon, "rope," margin "Hebrew `a rope of rushes,’ " the King James Version "hook" (Job 41:2): "(burning) rushes," the King James Version "caldron" (Job 41:20); "rush," the King James Version "bulrush" (Isa 58:5); "rush" in Isa 9:14; 19:15, used of the humble and lowly folk as contrasted with the "palm branch," the highest class): The word ’aghmon comes from ’agham, meaning a marsh (see Pool), being transferred from the place of the things growing there. The word doubtless includes not only the rushes--of which there are several kinds in Palestine--but also members of the sedge family, the Cyperaceae.
See also REED.