Cephalanthera longifolia

Cephalanthera longifolia, known by the common names Narrow-leaved Helleborine or Sword-leaved Helleborine, is an herbaceous perennial plant with rhizome of the family Orchidaceae. It is native to light woodland, widespread across Europe, Asia and North Africa from Ireland and Morocco to China. This includes Iran, Russia, Kazakhstan, Turkey, Algeria, India, Pakistan, Germany, Italy, France, Spain, Portugal and many other countries. Cephalanthera longifolia reaches on average 20–60 centimetres (7.9–23.6 in) of height in typical conditions. This orchid has erect and glabrous multiple stems. The leaves are dark green, long and narrowly tapering (hence the common name of Sword-leaved Helleborine). The inflorescence is a lax, five to twenty-flowered spike with the bell-shaped flowers ascending in an oblique spiral. The flowers are white, about 1 cm (0.4 in) long, with a yellow-edged labellum and they usually open only during the warmest and brightest hours of the day. This plant can be found in bloom from April to June, depending on location and altitude. The fruit is a dry capsule and the dust-like seed is dispersed by the wind. One unusual characteristic of this species is that some individuals are achlorophyllous (lacking green pigment) and take all their nutrition from mycorrhizal fungi. The flowers are pollinated by solitary burrowing bees. The flowers produce little nectar and the yellowish dust on the labellum which the insects collect is of little nutritional value. The actual pollen is contained in two pollinia which adhere to the hairs on the bee's back. An investigation in Estonia determined that the mycorrhizal partners of this orchid species include Thelephoraceae and Helotiales. Another investigation indicated 9 mycorrhizal partners (still fewer than those recorded for Cephalanthera damasonium): Bjerkandera adusta, Phlebia acerina, Sebacinaceae, Tetracladium sp., and Tomentella sp. Cephelanthera longifolia is vulnerable to grazing by deer. Cephalanthera longifolia is common in some parts of its European range, such as southern France and Spain, but endangered particularly in northern areas such as Belgium. In Britain and Ireland it is a quite uncommon and declining species, and conservation work is being carried out at a number of sites to safeguard it (see also Galley Down Wood). In 2007 it was listed as a priority species under the UK Biodiversity Action Plan. The charity Plantlife International is leading this work in the United Kingdom. Sword-leaved Helleborine usually grows in damp woodland places (mainly oak and beech), forest edges and rocky slopes. These plants prefer calcareous soils and in well exposed places, at an altitude of 0–1,400 metres (0–4,593 ft) above sea level.