Ranges in height from 10-60 cm, with a basal cluster of four to eight shiny, oblong, blunt-tipped leaves, and two or three stem leaves. Most plants have darkly-spotted leaves, the degree of spotting being highly variable. There are 20-50 pinkish-purple flowers in a loose spike, which can be lax in woodland plants. The sepals spread upwards, almost touching above the loose hood formed by the upper sepal and blunter petals. The lip is broad, three-lobed with a notch in the central lobe, and with the crenated side lobes slightly reflexed. The centre of the lip is pale and marked with dark spots. The spur is stout, blunt and upturned. When the flowers are just opened the scent is usually sweet, like honey, but soon smells strongly of tom-cat's urine, a device which may serve to inform visiting insects that pollination has already occurred. It is normally monocarpic, depending entirely on seed for future generations, which explains the wide fluctuation in the number of flowering plants from year to year. White-flowered plants alb are not infrequent, and may form a high percentage of some populations, as in The Burren in Ireland; they have not been recorded in Scotland. Pink-flowered plants are less common. Plants with 'broken-coloured' flowers brf - pale pinkish-purple, but flecked all over with mauve spots - were first recorded in Gloucestershire in 1988, where they reappeared in 1991; such plants have also been seen in Wiltshire (1989), Kent (1991) and Sussex (2001).
CONFUSING SPECIES: Very small, dark coloured plants with unspotted leaves may superficially resemble Green-winged Orchid, but lack the parallel green veins on the hood of that species.
HYBRIDS: The uncommon hybrid with Green-winged Orchid was recorded in Westmorland in 1985.
Grows in a wide variety of habitats on neutral or calcareous soils, flourishing in particular in broadleaved woodland and coppices. It also grows on calcareous grassland, limestone pavement, road verges and beside damp flushes on coastal cliffs.Buff-tailed Bumblebees frequently visit the flowers. Less common pollinators recorded are solitary bees (possibly Eucera longicornis) and cuckoo bees of the genus Psithyrus (Bombus).Some populations have been lost from broad-leaved woodlands which have been cleared and replanted with conifers.