butomus

The flowering Rush, or water gladiole, which grows by the banks of rivers is called botanically "butomus," from the Greek, _bous_, an ox, and _temno_, to cut, because the sharp edges of the erect three-cornered leaf-blades wound the cattle which come in contact with them, or try to eat them.

Herbal Simples Approved for Modern Uses of Cure William Thomas Fernie

Near the water's edge, mingling with sedges, flags, marsh-mallows, bur-reed, and alisma, were the golden flowers of the shrubby lysimachia in dense multitudes, while from the canal itself rose many a spike of water-stachys, with here and there blossoming butomus, near the fringe of the banks.

Two Summers in Guyenne Edward Harrison Barker 1885