(L.) Fritsch
Description
Cephalanthera longifolia (L.) Fritsch is a terrestrial orchid with one of the widest ranges in its genus, extending from western Europe and North Africa across temperate Asia to the Himalaya. GBIF records it from France, Switzerland, Austria, Germany, Spain, Italy, Sweden, Britain, Greece, China and many other countries, with over 141000 occurrences reflecting its abundance in the western part of its range. It grows in dappled shade in deciduous and coniferous woodland, scrub and grassy banks, often on calcareous soils, from near sea level to about 2500 m. In the eastern Himalaya it reaches the montane forests of Bhutan, recorded at Jakar around 2400 m in May and at Paro near 1950 m in April.
The plant arises from a short rhizome with fleshy roots and produces an erect, leafy stem. The leaves are numerous, narrowly lanceolate to linear-lanceolate, sheathing at the base, longer than the internodes and noticeably keeled. The lax terminal raceme bears several pure white flowers that scarcely open, remaining narrowly campanulate; the sepals and petals are lanceolate and acute, and the labellum is shorter, divided into a basal hypochile with a small spur-like sac and an apical epichile marked with orange-yellow ridges that guide pollinators. The ovary is twisted and glabrous, ripening into an erect capsule.
Cephalanthera belongs to subtribe Limodorinae of tribe Neottieae and, like its relatives, is partially mycoheterotrophic, drawing carbon from ectomycorrhizal fungi associated with forest trees. Cephalanthera longifolia is globally secure given its enormous range, but it is locally scarce and legally protected in parts of northern Europe where suitable woodland is fragmented. Its trans-Palaearctic distribution makes it a notable example of a widespread orchid reaching its eastern limit in the Himalayan forests.
Author: (L.) Fritsch · Sources: POWO (Kew), GBIF, Flora Europaea, Flora of Bhutan, Flora of China, Delforge monograph of Orchids of Europe