Spiranthes spiralis
| Autumn lady's-tresses | |
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| Scientific classification | |
| Kingdom: | Plantae |
| (unranked): | Angiosperms |
| (unranked): | Monocots |
| Order: | Asparagales |
| Family: | Orchidaceae |
| Genus: | Spiranthes |
| Species: | S. spiralis |
| Binomial name | |
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Spiranthes spiralis (L.) Chevall. |
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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 in length. In late summer an unbranched stem of about 10–15 cm tall is produced with approximately four sheath-shaped leaves. The white flowers about 5mm long have a green spot on the lower lip and 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 long and ¾-1½ cm 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 ones every few years, and will during hard times not surface at all. The stem is grayish green, usually 7-20 (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 (exceptionally 5½) cm long and ¾-1¾ cm 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.
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Wikipedia