A tuberous perennial herb found on chalk in grassland, scrub, woodland glades and a chalk-pit. It was planted on industrial waste ground in S. Lancashire, and in new sites in Cambridgeshire and Kent. Lowland.
Habitat destruction and collecting caused a decline in this species until it was considered extinct in the 1920s. It was re-found in Buckinghamshire in 1947 and Suffolk in 1954, where populations are stable, and it appears sporadically in two Oxfordshire sites.
Eurosiberian Temperate element, with a continental distribution in W. Europe.
Light (Ellenberg): 7
Moisture (Ellenberg): 3
Reaction (Ellenberg): 9
Nitrogen (Ellenberg): 2
Salt Tolerance (Ellenberg): 0
January Mean Temperature (Celsius): 3.4
July Mean Temperature (Celsius): 16.3
Annual Precipitation (mm): 694
Count of 10km squares in Great Britain: 19
Count of 10km squares in Ireland: 0
Count of 10km squares in the Channel Isles: 0
RDB Species Accounts
Orchis militaris L. (Orchidaceae)
Status in Britain: VULNERABLE. WCA Schedule 8. Var. tenuifrons is ENDEMIC.
Status in Europe: Not threatened.
In Britain, O. militaris is a plant of grassland, scrub and woodland glades on chalk, occurring regularly at one site in Buckinghamshire and one in Suffolk. When first discovered in the former county, it grew in open chalk downland, but woodland has since developed on the site (planted beech, and naturally occurring ash, field maple, hawthorn, yew), and the orchid has become confined to a glade. Associated herbs are woodland and wood-edge species including Brachypodium sylvaticum, Chamerion angustifolium, Festuca rubra, Fragaria vesca, Hedera helix, Mercurialis perennis, Rubus fruticosus, Viola riviniana and robust mosses including Rhytidiadelphus triquetrus. Its Suffolk site is an old chalk pit, now surrounded and partly shaded by a plantation of mainly sycamore and birch with an understorey of bramble and privet. A patchy ground cover of herbaceous species including Daphne mezereum, Festuca rubra, Inula conyza, Mycelis muralis, Poa pratensis, Ranunculus repens and Torilis japonica is interspersed with patches of abundant hypnoid mosses and some bare ground (Farrell 1985).
New shoots may first appear above the ground in early January as small crocus-like buds, but growth is slow until May, when the flower stalk rapidly elongates. The first shoots to emerge are usually the ones which flower, later ones remaining vegetative. Flowering is generally between the end of May and early June. Rather few insect species visit the flowers in Britain (Farrell 1985), but ants feed on the nectar. The main pollinators are likely to be hoverflies and bumblebees, the latter having been observed removing pollinia (Farrell, pers. obs.). Seedpods ripen and turn purplish-green in August, though a relatively small percentage of plants set seed in Britain: 2-28% reported by Summerhayes (1951), and 3-10% observed in Suffolk. Because of poor seed-set, vegetative reproduction is likely to be important in British populations. Like many orchids, development from germination to flowering is likely to take several years, and individual plants can live for at least fifteen years.
The Suffolk site holds by far the largest population with up to 2,000 flowering spikes. In Buckinghamshire the colony is much smaller, currently comprising about 50 plants. Two other native sites are known, both in scrubby chalk grassland in the Oxfordshire Chilterns, but in those sites the appearance of plants has always been sporadic, and no more than six have appeared in any year. It formerly occurred in Surrey, Hertfordshire, Middlesex, and Berkshire, but records from Kent are almost certainly erroneous (Philp 1982). Sell & Murrell (1996) assign the Suffolk population to var. militaris, widespread in Europe, and the Chilterns plants to var. tenuifrons, which they regard as endemic to Britain, and therefore the more important taxon in conservation terms.
Habitat management in recent years has resulted in significant increases in both of the main populations. Because plants in dense shade may not flower or produce any aerial parts, conservation management has been directed towards keeping the canopy open in woodland glades by felling trees and lopping branches. Recent clearing in Buckinghamshire has resulted in the emergence of O. militaris in re-opened areas. Also important is the regular control of shrubs and removal of moss (Farrell 1991). At the Suffolk site it seemed that small mammals were nibbling off many shoots, taking advantage of the protective cover of blanketing moss and making runs under it. Removal of the moss reduced the damage.
O. militaris is widespread and locally abundant in Europe, ranging from south-east Sweden and Russia through all the central European countries to northern Spain, central Italy, former Jugoslavia, Romania, Bulgaria and European Turkey, and eastwards to the Altai Mountains and Lake Baikal. Habitats in continental Europe are more varied, including sand-dunes, roadside verges, wet meadows, river shingle and abandoned cultivated ground, but mainly on calcareous substrates.
PLANTATT - Attributes of British and Irish plants. (.zip 1455KB) This dataset was compiled and published in 2004, and last updated in November 2008. Download includes an Excel spreadsheet of the attributes, and a PDF explaining the background and nomenclature. Note that the PDF version is the booklet as published, whereas the Excel spreadsheet incorporates subsequent corrections. A hardcopy can be purchased from the Centre for Ecology and Hydrology.
Atlas text references
1985. Biological Flora of the British Isles. No. 160. Orchis militaris L. (O. galatea Poir, O. rivini Gouan, O. tephrosanthes Willd. & Sw.). Journal of Ecology. 73:1041-1053.
1986. Atlas of north European vascular plants north of the Tropic of Cancer. 3 vols.
1998. Demographic properties of an outlier population of Orchis militaris L. (Orchidaceae). Journal of the Linnean Society. 126:95-107.
1965. Vergleichende Chorologie der zentraleuropäischen Flora. Volume 1. 2 vols.
1991. The orchids of Suffolk.
1996. Flora of Great Britain and Ireland, 5. Butomaceae-Orchidaceae.
1998. Population biology of the rare military orchid (Orchis militaris L.) at an established site in Suffolk, England. Botanical Journal of the Linnean Society. 126:109-121.
1999. British Red Data Books. 1. Vascular plants, edn 3.