Aceras anthropophorum

Aceras anthropophorum (L.) Aiton f.

Man orchid

Status: scarce

This is a lowland plant of old chalk and limestone quarries, calcareous pastures and roadsides. It is able to tolerate considerable shade and grows best at the edge of scrub, often among coarse grasses such as Brachypodium pinnatum. It does not do well in heavily grazed pastures and can be eliminated by continuous, heavy grazing. It usually grows in association with other orchids, such as Anacamptis pyramidalis, Dactylorhiza fuchsii, Gymnadenia conopsea and Listera ovata.

A. anthropophorum persists vegetatively by annual `side-by-side' tuber replacement, whereby the ovoid tuber used in producing an inflorescence is replaced by a new tuber which began growth about eight months previously. Leaves push through in November and are winter green, usually dying as flowers on the inflorescence open in late May or early June. Capsules are formed and copious seed dispersed by late June, early July. Studies of individually marked plants at Totternhoe, over a period of 20 years, have established that individual plants live for up to ten years and that flowering may occur for up to five years in succession (the species is only rarely monocarpic). The fate of the huge quantities of seed produced is not known, but most must perish as new localities for this species are rare. Germination of the seed will occur only in the presence of a compatible fungal associate, but details of such a relationship are at present inadequately researched.

A. anthropophorum has decreased in Britain. Most East Anglian populations were extinct by 1930 (Perring & Walters 1962) as a result of the ploughing of chalky pastures in the late 19th century. Further Suffolk sites were ploughed up or used as airfields in wartime or were on roadside verges which have deteriorated because of inappropriate cutting regimes or spray-drift (Sanford 1991). The species is, however, still plentiful at sites in Kent and at certain favourable localities elsewhere, and populations in excess of 10,000 plants have been reported from old quarry sites, such as Barnack Hills and Holes, in some years. Some chalk-pit sites are threatened by use as rubbish tips, euphemistically termed `land-fill'.

A. anthropophorum has a distinctly southern and western distribution in Europe, reaching its northernmost limit in England and extending in the Mediterranean region as far east as Rhodes and Cyprus; it also occurs in Morocco and Algeria.

T. C. E. Wells