Perennial, herbs, raraly reaching1 m high; rootstock horizontal, bearing many, sessile, aromatic tubers; leaves linear-lanceolate, 10-30 cm long, acuminate at apex, glabrous beneath, ligules membranous; spikes oblong, cylindric, 4-5 cm long, many flowered; bracts about 2-3 cm long, green, suborbicular, cuspidate; calyx cylindric; corolla segments lanceolate, subequal, greenish yellow; lip shorter, stamen dark purple, as long as the lip, labellum often with yellow spots; anther dark purple, with long beak; lateral staminodes ovate or absent; ovary glabrous, 3-celled, ovules many, superposed, style filiform, stigma small, subglobose; capsules oblong, 3-valved; seeds ovoid or oblong.