In Europe this genus is represented by a single species, this being the small and unremarkable P. albida, an orchid known to many as the Small White Orchid.
This genus was known in older literature as Leucorchis
and the name is still employed today by some botanists who are as yet
unconvinced by the latest nomenclature changes in respect of this
Most experts accept that this genus is extremely close to Gymnadenia
but not all go as far as Delforge and accept that they are in fact two
groups within the same genus. The two families share many
characteristics and not least reproductive mechanisms and pollinators,
they do however differ in having perianth segments that project forward
to form an enclosed helmet.