Cypripedium acaule - Pink Lady's Slipper Orchid, or Mocassin Flower - (Orchidaceae)

This orchid, which is also known as Stemless Lady's Slipper, is widespread across Canada and the United States.

Cypripedium acaule

The main habitat of Pink Lady's Slipper is coniferous forests, but it can also turn up in meadows, roadside ditches and even on railway sidings and cuttings.

Side view of Pink Lady's Slipper Orchid

This orchid has a pair of basal leaves from which grow tall, leafless stems each of which bears a single flower. In colouring it is usually pink, but there is also a white form - Cypripedium acaule forma album.

Close up of Pink Lady's Slipper Orchid

Photographs by kind permission of Gareth and Margaret Howell

The peak flowering time for Cypridpedium acaule is in June, and at good sites they carpet the ground.

In Europe, our closest relative to the Pink Lady's Slipper Orchid is Cypripedium calceolus - the Lady's Slipper Orchid. In the UK, the known native plants were reduced to just one specimen, in Yorkshire. Today the Lady's Slipper Orchid is the subject of a re-introduction programme which is taking place at Gait Barrows National Nature Reserve in Lancashire. In other northern European countries, including Sweden, Norway, Finland, Denmark, Austria and Switzerland, the Lady's Slipper Orchid still flowers relatively freely, but it cannot be described as common anywhere in its range.