Perennial with tap root. Stem erect, up to 1 m high. Branches erect or erect-patent forming a narrow panicle. Leaves all lanceolate, narrowed at both ends, acute, crispate, up to 30 cm long and up to 6 cm broad, broadest in the middle; petiole shorter than the blade; stem leaves similar, upwards gradually smaller, narrower and with shorter petiole. Flower whorls many-flowered, contiguous, the lowest ones only remote and with a subtending leaf. Pedicels thin, of varyig length, usually about twice as long as the valves. External perianth segments appressed to the valves, nearly as long as half of the breadth of the valves. Valves usually 4-5 mm long and broad, rotundate or subtriangular-cordate, finely articulate, entire or subentire, all or the anterior one grain bearing. Nut c. 3 mm long, brown, broadest below the middle.