Perennial herb spreading by means of underground rhizomes and forming rosettes of leaves. Leaves are narrow, up to 20 cm long, bright yellowish-green. Flowering stalks can be as much as 100 cm tall. Flowers are white, up to 10 mm long. Fruit is a dry capsule tapering at the tip. Rhizome; browinish-grey, flattened, up to 1 cm in diameter, but usually less, tufted on the upper surface with leaf bases and marked with circular stem scars, numerous branched wiry rootlets on the lower circular stem scars on the lower. Fracture, mealy, white.

[1] British Herbal Pharmocopoeia 1983 Published by the British Herbal Medicine Association ISBN 0 903032 07 4.
[2] Herbal Materia Medica Course Notes For Diploma of Naturopathy and Diploma of Herbalism Students by Lydia Mottram.
[3] Potter's New Cyclopaedia of Botanical Drugs and Preparations  R.C. Wren Revised by Elizabeth M. Williamson and Fred J Evans. First published in Great Britain in 1988 and reprinted in 1989 and 1994 by the C. W. Daniel Company Limited. 1 Church Path, Saffron Walden Essex. Published 1988 Printed and bound by Biddles, Guildford ISBN 085207 1973.
Images
1. plants.ces.ncsu.edu by Eleanor, CC BY-NC-2.0
2. pennherb.com

Saponins, based on diosgenin.^[1] Volatile oil, resin.^[2]
References
[1] Marker, R.E. et al. (1940) J. Chem. Soc. 60, 2620
[2] Potter's New Cyclopaedia of Botanical Drugs and Preparations  R.C. Wren Revised by Elizabeth M. Williamson and Fred J Evans. First published in Great Britain in 1988 and reprinted in 1989 and 1994 by the C. W. Daniel Company Limited. 1 Church Path, Saffron Walden Essex. Published 1988 Printed and bound by Biddles, Guildford ISBN 085207 1973.