Spiranthes spiralis

Spiranthes spiralis, commonly known as autumn lady's-tresses, is an orchid that grows in Europe and adjacent North Africa and Asia. It is a small grey-green plant. It forms a rosette of four to five pointed, sessile, ovate leaves about 3 cm (1.2 in) in length. In late summer an unbranched stem of about 10–15 cm (3.9–5.9 in) tall is produced with approximately four sheath-shaped leaves. The white flowers are about 5 mm (0.20 in) long and have a green spot on the lower lip. They are arranged in a helix around the upper half of the stalk. The species is listed in Appendix II of CITES as a species that is not currently threatened with extinction but that may become so. Autumn lady's-tresses are legally protected in Belgium and the Netherlands. Autumn lady's tresses is a polycarp, perennial, herbaceous plant that remains underground during its dormancy in summer with tubers. The species has thirty chromosomes (2n=30). Underground there are two to four (or exceptionally six), egg-shaped or ovate-oblong, hard tubers which are usually 1–3 cm (0.39–1.18 in) long and ¾–1½ cm (0.3–0.59 in) in diameter, slightly tapering towards the tip. They are pale brown and smooth with short transparent hairs on the outside. These tubers, as in many orchids, have an earthy musty smell, originating from the mycorrhiza. There are no thick filamentous secondary roots as in many other orchids. The plant needs many years to grow large enough (eight years) to produce above-ground parts, and to produce a flowering stalk (another three years). Even then, it mostly flowers once every few years, and will during hard times not surface at all. The stem is greyish green, usually 7–20 cm (2.8–7.9 in) (in Southern Europe exceptionally 40 cm) high, unbranched, erect, and terete. Especially further up, the stem is covered with short transparent glandular hairs. Below the flowers stand three to seven grayish green, acute leaves that envelop the stem, with membranous edges and three to five veins. Sometimes the withered leaf remains of the rosette of the previous year are still visible at the base of the stem. The new leaves, which appear at the same time or after the flower stem, stand with four to five together in a rosette beside the stem. They are 2–4 cm (0.79–1.57 in) (exceptionally 5½ cm) long and ¾-1¾ cm (0.3-0.69 in) wide, blue-green, very glossy, sessile, oval and have a pointed tip and translucent entire edges. They have three to five keeled veins. Plants in the Mediterranean can be considerably more robust than those in Western and Central Europe. The inflorescence is a slender spike of 3–12 cm (1.2–4.7 in) (exceptionally 20 cm) long, with usually ten to twenty-five (rarely as few as six or as many as thirty) flowers. They are set in a single row, usually in a clockwise or counterclockwise spiral winding around the axis, or rarely all to one side. Each flower is subtended by a pale green, lanceolate bract. This shelters the base of the flower, tapers, bends toward the tip, has white edges and scattered glandular hairs at the base. They are usually 9–13 mm (0.35–0.51 in) long and 3–5 mm (0.12–0.20 in) wide. The flowers are very small, ± ½ cm (0.2 in), white, and spread a fragrance that is said to by reminiscent of lily of the valley, vanilla or almonds. The flowers produce nectar unlike in many other orchids. The flower has no spur. Outer tepals are oblong-ovate, slightly tapering to a blunt tip, 6–7 mm (0.24–0.28 in) long, white with a light green vein, have a ciliate or very finely serrated edge, and on the outside with little glandular hairs. Inner perianth leaves are white, elongate with a blunt tip, a vein and adhere with the slightly longer upper outer perianth leaf, thereby forming an upward decurved upper lip. The lower lip is pale green with a wide irregular jagged edge of crystal-like transparent white growths, oblong, approximately 4–5 cm (1.6–2.0 in) long and 2½–3 mm (0.10–0.12 in) wide, trough-shaped, rounded and without lobes and at its top bending down. Both lips give the flower as a whole a trumpet shape. The lower lip encloses the column (merger of the stamen and style) at the base, and there are also two white, glossy, round, nectar-secreting glands, each with a ring of papillae around their base. The small column is green.