Spiranthes spiralis, (L.) Chevall, 1827, 1827

D. M. Moore (ed.), 1980, CCIII Orchidaceae, Flora Europaea, Vol 5: Alismataceae to Orchidaceae, Camebridge: Cambridge University Press, pp. 325-350 : 330

1. S. spiralis (L.) Chevall .,

Fl. Gén. Env. Paris 2: 330 (1827) (S. autumnalis L. C. M. Richard ).

Roots tuber-like, oblong- ellipsoid. Stem 6-20(-35) cm, glandular-pubescent, bearing 3-7 closely appressed, lanceolate scale-leaves. Foliage-leaves 2-3-5 cm, ovate-elliptical, acute, glabrous, glaucous, in a basal rosette, usually withered at anthesis, but next year’s rosette appears during anthesis beside the flowering stem. Spike 3-10 cm, slender, with 6-20 flowers in one spiral row. Bracts 6-7 mm, acuminate. Perianth-segments 6-7 mm, oblong, white, the upper 3 conni­ vent and forming with the labellum a tube enclosing the column, the outer lateral segments patent. Labellum 6-7 mm, with up­ wardly curved margins and undulate-crenulate apex, yellowish- green. Flowering in autumn or late summer. 2ft = 30.

Grassland.

S., W. & C. Europe, extending northwards to E. Denmark. All except Az Fa Fe Is No Rs (N, B, C, K, E) Sb Su.

Even among orchids this species is noteworthy for the irregu­ larity of its flowering; in certain regions, especially in the northern part of its range, populations often do not flower for many seasons.