Hairless perennial, 60-100 cm tall. Leaves sometimes absent at flowering time.
Flowers few to many in a terminal raceme, up to 30 cm long. Pedicels short, up to 1.5 cm, set at an angle to the flowers.
Outer perianth segments 18-20 × 5 mm, yellow-green with a green central stripe; inner similar but slightly broader, c. 7 mm wide. Capsule 15-18 mm.