Autumn Lady's Tresses (Spiranthes spiralis
Etymology
Spir- = twisted, anthos =flower
Spiralis = spiralling.
1548 Turner; The Names of Herbes. "Satyrion ...groweth besyde Syon, it bryngeth furth whyte floures in the end of harveste, and it is calledLady traces" (Pearman). Satyrion is an old collective name for orchids.
The Plant
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Autumn Lady's Tresses, Noar Hill, Hants 23.8.17 (IMG 9030) |
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Autumn Lady's Tresses, Banbury, Oxfords 1.9.19 (IMG 0807) |
Autumn Lady's Tresses, Hatchet Heath, Hants 12.8.20 (IMG 1589)
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Autumn Lady's Tresses, Noar Hill, Hants 23.8.17 (IMG 8953S)  Autumn Lady's Tresses, Hatchet Heath, Hants 12.8.20 (IMG 1615)   Autumn Lady's Tresses, Greenham Common, Hants 13.8.20 (IMG 1674)  Autumn Lady's Tresses, Greenham Common, Hants 13.8.20 (IMG 1631-8S) |
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Autumn Lady's Tresses, Noar Hill, Hants 23.8.17 (IMG 9053S)  Autumn Lady's Tresses, Greenham Common, Hants 13.8.20 (IMG 6793-804S)  Autumn Lady's Tresses, Greenham Common, Hants 13.8.20 (IMG 6806)  |
Autumn Lady's Tresses, Greenham Common, Hants 13.8.20 (IMG 6810)
Stems to 15cm. Flowers in a single spiral. (Stace)
Leaves
Rosette at base of stem, with 4 or 5 leaves, produced in the autumn and lasting through the winter, dying away in late May, June. (Summerhayes). Obovate-elliptic. (Stace)
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New leaf rosettes, Banbury, Oxfords. 8.10.19 (IMG 1477) |
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New leaf rosette, September , Somiedo, Northern Spain 16.9.18 (IMG 2300) |
Leaf Edge and Tip
Virtually entire without any teeth.
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Leaf Edge, Upper Side x100 (IMG 3891S) Field of View 1 mm |
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Leaf edge - Upper side x100 (IMG 0943S) Field of View 1mm |
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Leaf apex - Upper side x40 (IMG 0947S) Field of View (vert) 2.5mm |
Roots
Thick, fleshy tubers (Summerhayes). Vegetative spread is possible - lateral buds on the stem may develop separate root tubers and eventually a distinct individual
Seeds
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Seeds (IMG 3874) x100 Field of View 1mm |
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Seeds (IMG 3875) x 100 Field of View 1mm |
My measurements are:
Average seed length x width 0.404mm x 0.142mm (n=5, Noar Hill, Hants). L:W 2.8
Seed Pods
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In fruit, Noar Hill September 8.10.18 (IMG 2963) |
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Seed pods from Noar Hill with Scale (IMG 3094) |
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Seed pods from Banbury with Scale (IMG 3094) |
My measurements are:
Average seed pod length x width 5.98 x 2.92mm (n= 7, from Noar Hill, Hants and Banbury, Oxfords) L:W 2.6
Seed pods borne on the stem at an angle of 22.5 degrees from the upright.
On one spike with 11 flowers only 4 were fertilised, at positions 3, 4, 5 and 6 from the bottom of the inflorescence.
Habitat
Short permanent turf (including lawns) or other short vegetation; grassy dunes. It can be abundant. Well drained. Slight preference for calcareous soil.
Mychorrhiza
No data.
Pollination
Carry scent in the daytime. Pollinators are mainly Hymenoptera (Bombus sp. and Apis mellifera). (Claessens and Kleynen). The fruit set percentage averaged 52.7% in 24 studies in Europe (Claessens and Kleynen), ranging from 22% to 93%. I measured 2 spikes in a small population in Banbury: the average was only 18%.
Flowering time
Analysing the BSBI records post 2000, but excluding the Channel Isles, and any records where the date is not given in full gives 3711 records for Britain and Ireland. I think it can be assumed that the vast majority of records are made when plants are in flower. Looking at the median date for these records split into 6 latitudinal zones gives the following flowering dates across the country:
South of of a line of latitude through Bristol, 2448 records, median date 30 August
Bristol to Birmingham, 988 records, median date 31 August
Birmingham to Manchester 186 records, median date 29 August
Manchester to Carlisle 65 records, median date 25 August
Carlisle to Glasgow no records
North of Glasgow no records
Surprisingly there does not seem to be a south to north progression in flowering times; if anything plants in the north seem to flower a little earlier than in the south.
The median for Ireland was 31 August, (249 records) so there does not seem to be an east-west bias either.
For what it is worth I have seen it in flower in the Cantabrian mountains in Spain in late September.
Distribution in Britain and Ireland
BSBI records from 2000
Found in 66 vice counties with most records from South Hampshire, VC11 (514) and Pembrokeshire, VC45 (567), though the latter's total is probably inflated by multiple records from a few localities. In 2000-19 it was found in 1260 monads, and is becoming more widespread (monads in 1960-79: 257, and in 1980-99: 1260), though there may of course have been more recording activity in the more recent decades.
Distribution Worldwide
Southern Eurasian distribution, as far north as Denmark, northern Germany, Poland to the Urals. Abundant in the Mediterranean, from Spain to Greece, occurring also in North Africa, Asia Minor, Syria to the Caucasus. Dependent on autumn and winter rain when the root mycorrhiza are active, but can survive summer drought.
Hybrids and Recognised Varieties
None
References
Pearman: Discovery of the Native Flora of Britain and Ireland - Pearman D 2018
Claessens and Kleynen: Flower of the European Orchid -Claessens J and Kleynen J 2011
Summerhayes: Wild Orchids of Britain - Summerhayes VS 1951
Stace: New Flora off the British Isles - Stace C 4th Edn, 2019
Updated 3.2021
