Small White Orchid (
Etymology
Pseudorchis = false orchis
albida = whitish, a reference to the flower colour
1670 Ray; "...This we found on the back of Snowdon-hill, by the way leading from Llanberis to Carnarvan" VC49 (Pearman)
The Plant
Habitat
Keltneyburn, Perthshire 26.6.18 (IMG 8923)
Whole Plant
Keltneyburn, Perthshire 26.6.18 (IMG 8905)
Inflorescence
South Stainmore 17.6.19 (IMG 5831-8S)
Description
Jersáková et al give a comprehensive species account of the species in Britain.
Stems to 20 (40) cm. Flowers in a cylindrical dense spike. (Stace)
Leaves
4 to 6 leaves in lower part of stem, the lower ones being broad and blunt, the upper ones quite small and narrow.
Leaf Edge
Roots
Two tubers rather like two minute parsnips, tapering gradually downwards, and often split, almost to the base into several parts (Summerhayes).
Seeds
No details
Seed Pods
No details - as yet I have not met the challenge of finding plants in fruit.
Habitat
Short grassland, - upland pastures - usually base rich (Stace)
Mychorrhiza
No data.
Pollination
Pollinators are micromoths, inter alia Chrysotteuchia culmella and Crambus species, attracted by the plant's sweet scent, but other insects might also play a part. In 6 European studies fruit set ranged from 57 to 92% with an average of 80%. (Claessens and Kleynen)
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 1331 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 5 latitudinal zones, and separately Wales and Ireland gives the following flowering dates across the country:
Wales, 13 records, median date 30 June, almost all from a single locality at altitude
Distribution Worldwide
It belongs to the northern montane group of British orchids, found in most of Europe but absent from the Mediterranean lowlands. It is not restricted to Europe and is recorded from north temperate Asia across to Kamchatka and the northern part of North America from Alaska across to Newfoundland (Summerhayes, Kühn et al).
South Stainmore 30.6.18 (IMG 9439)
Leaves
4 to 6 leaves in lower part of stem, the lower ones being broad and blunt, the upper ones quite small and narrow.
Leaf Edge
Leaf Edge, Upper Side x100 (IMG 3281-4S) Field of View 1 mm
Between 16 and 18 bell-shaped teeth per mm. Each tooth averages 0.066mm wide, measured from the gap to one neighbour to that of the other. The teeth average a height above the bottom of the gaps to the neighbours of 0.037mm.
Leaf Tip
Leaf Tip, Upper Side x40 (IMG 3277) Field of View 2.5 mm
I measured the angle of one leaf tip at 45°.
Roots
Two tubers rather like two minute parsnips, tapering gradually downwards, and often split, almost to the base into several parts (Summerhayes).
Seeds
No details
Seed Pods
No details - as yet I have not met the challenge of finding plants in fruit.
Habitat
Short grassland, - upland pastures - usually base rich (Stace)
Mychorrhiza
No data.
Pollination
Pollinators are micromoths, inter alia Chrysotteuchia culmella and Crambus species, attracted by the plant's sweet scent, but other insects might also play a part. In 6 European studies fruit set ranged from 57 to 92% with an average of 80%. (Claessens and Kleynen)
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 1331 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 5 latitudinal zones, and separately Wales and Ireland gives the following flowering dates across the country:
Wales, 13 records, median date 30 June, almost all from a single locality at altitude
Ireland, 481 records, median date 15 June, mostly at low altitude
England south of a line through Manchester, no records
England south of a line through Manchester, no records
Manchester to Carlisle 219 records, median date 20 June
Carlisle to Glasgow 37 records, median date 26 June
Glasgow to Inverness 472 records, median date 25 June
Carlisle to Glasgow 37 records, median date 26 June
Glasgow to Inverness 472 records, median date 25 June
North of a line through Inverness, 107 records, median date 20 June
Surprisingly there does not seem to be a south to north progression in flowering times; altitude is probably more important.
Distribution in Britain and Ireland
Surprisingly there does not seem to be a south to north progression in flowering times; altitude is probably more important.
Distribution in Britain and Ireland
BSBI Records 2000 - 2020
Found in 42 vice counties with most records from Fermanagh, VCH33 (201) and in Britain, East Inverness-shire VC96 (130), though the former's total is probably inflated by multiple records from a few localities. In 2000-19 it was found in 287 monads, and is appears to be gradually spreading (monads in 1960-79: 81, and in 1980-99: 232), though there may of course have been more recording activity in the more recent decades.
Distribution Worldwide
It belongs to the northern montane group of British orchids, found in most of Europe but absent from the Mediterranean lowlands. It is not restricted to Europe and is recorded from north temperate Asia across to Kamchatka and the northern part of North America from Alaska across to Newfoundland (Summerhayes, Kühn et al).
Kühn et al name two subspecies, subsp. albida to which British plant belong and subsp. straminae.
Hybrids
Pseudorchis albida is the only member of the Pseudorchis genus; It was formerly ranked in the Gymnadenia genus (Summerhayes for example named it as Gymnadenia albida) and there is one intergeneric hybrid known from Britain, Pseudorchis albida x Gymnadenia borealis = x Pseudadenia schweinfurthii, with records from 2 vice counties (VC69 and VC96) and 3 monads. The median flowering date is for all records is 27 June, though the number of usable records is only 6. I saw it in flower on 30 June.
Pseudorchis albida is the only member of the Pseudorchis genus; It was formerly ranked in the Gymnadenia genus (Summerhayes for example named it as Gymnadenia albida) and there is one intergeneric hybrid known from Britain, Pseudorchis albida x Gymnadenia borealis = x Pseudadenia schweinfurthii, with records from 2 vice counties (VC69 and VC96) and 3 monads. The median flowering date is for all records is 27 June, though the number of usable records is only 6. I saw it in flower on 30 June.
South Stainmore 30.6.18 (IMG 9447)
South Stainmore 30.6.18 (IMG 9439)
Perhaps more surprisingly there is also an intergeneric hybrid with a member of the Dactylorhiza genus, Dactylorchiza maculata x Pseudorchis albida = x Pseudorhiza bruniana. In the last 20 years there have been records from only one location, thus a single monad in VC96. It is a taxa that I have not seen, though I do know the exact location, because it is on private land. There are older records from the 1990's from the Isle of Skye; maybe I will try to refind it. The recent records (5) give a median flowering date of 23 June.
References
Jersáková et al Biological Flora of the British Isles: Pseudorchis albida (L.) Á. Löve & D. Löve, - Jersáková, J Malinová, T, Jeřábková , K and Stefan Dötterl, S
Journal of Ecology 2011, 99, 1282–1298 Pearman: Discovery of the Native Flora of Britain and Ireland - Pearman D 2018
Kühn et al: Orchids of Europe and the Mediterranean - Kühn, R., Pedersen, H. and Cribb, P. 2019
Kühn et al: Orchids of Europe and the Mediterranean - Kühn, R., Pedersen, H. and Cribb, P. 2019
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
Summerhayes: Wild Orchids of Britain - Summerhayes VS 1951
Stace: New Flora off the British Isles - Stace C 4th Edn, 2019
Updated 29.3.2021
